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United Kingdom: Royal Navy

Last modified: 2006-08-19 by rob raeside
Keywords: royal navy | white ensign | colours | pennant | paying off pennant | dunkirk little ships | shifting the colours | showing the flag |
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[UK naval ensign] image by Vincent Morley

See also:

History of the White Ensign

In origin there were three naval squadrons, of the Red, White and Blue, and they took these colours from those of the Union Jack. The division was made in the 1680s, if I remember correctly. Because the Red Ensigns of England and Scotland had already been established as merchant flags a Red Ensign with the Union in the canton became the merchant flag of Great Britain upon Union in 1707. This led to potential confusion - was that ship a merchantman or a member of the red squadron?

In 1864 it was decided to end this anomaly. Henceforth the White Ensign was reserved to the Royal Navy; the Blue Ensign undefaced to the Royal Naval Reserve and defaced with the appropriate departmental or territorial badge to government service; and the Red Ensign to the 'merchant navy' (as the term is in Britain).

Roy Stilling, 6 July 1996

Use of the White Ensign

I quote from the 1951 Admiralty Manual of Seamanship;

All H.M. ships in commission wear the White Ensign. It is worn at the ensign staff when in harbour; it is also worn at the ensign staff at sea whenever possible, but in bad weather, or when cleared for action, or during war, it is worn at the peak of the gaff on the mainmast, or on a suitable staff mounted in the after part of the ship.
I think that nothing has changed since then, except that the Navy now consists mainly of small ships in which, when at sea, it is usually more practical to fly the ensign from a mast rather than the ensign staff, particularly since many operate helicopters over the stern.

The White Ensign is flown at the peak of all Royal Navy/Royal Marines shore establishments, commanded by a commissioned officer, regardless of distance from the sea. There used to be a Naval Air Station near Nottingham, almost as far from the sea as you can get in Britain, but it was called H.M.S. Gamecock and flew the White Ensign. I can't remember if a commissioning pennant is flown at the masthead of shore establishments.

David Prothero, 14 July 1999

The Queen's Regulations for the Royal Navy, (London: HMSO, 1967) provides at paragraph 1210 that "In a fleet establishment commissioned as one of H.M. ships and similarly commanded, the masthead pennant is to be flown at the head of the flagstaff wherever fitted." From the context, "similarly commanded" means "commanded by a naval officer".

Joseph McMillan, 4 September 1999

Above the main entrance of the Ministry of Defence building in Whitehall are three flagpoles with the Royal Navy's white ensign, the British Army flag, and the RAF ensign flying in that order (from the observer's left to right).

Joseph McMillan, 23 September

Use as a battle ensign

Flying one or more additional flags in battle is a practice common to most navies. A single ensign might be shot away in the action, giving the impression that the ship had lowered its colours as a sign of surrender. In the Royal Navy the Battle Ensign is usually an extra large White Ensign, but during the First World War, Union Jacks, Blue Ensigns or Red Ensigns were flown as additional flags in case the White Ensign was mistaken for the rather similar German Naval Ensign.
David Prothero, 23 February 2006

Use as a distinguishing mark of a commanding officer with the royal commission

From the minutes of the 11th Meeting of the Committee for Imperial Defence held on the 26th May 1911, when the Canadian representatives were persuaded by some unusual arguments that their naval ships should fly the British White Ensign rather than the Canadian Blue Ensign.

Mr.Reginald McKenna. (First Lord of the Admiralty).
"There is one matter about which I think I ought to say something here, because it is a point, I think almost the only point, upon which we have not been able to come to a final agreement with the representatives of the Dominions in the matters relating to organisation, training and status - that is the question of the flag. I cannot help thinking that in the Dominions - in fact at home also - there is very considerable misunderstanding as to the meaning of our flags. Every ship of war in the British Navy carries two flags; it may carry more, but it always carries these two : it carries the Union Jack forward on what is called the jack-staff, and at the stern it carries the White Ensign. The meaning of the Union Jack is that that ship of war is a British ship of war, and I can trace back historically an unbroken record from 1634 that the flag carried upon the jack-staff is the flag that denotes nationality. The White Ensign on the other hand does not denote nationality at all. Its history is not so clear as the history of the Union Jack if you go back centuries. But for many years now it has had but one meaning. When a ship flies the White Ensign it means that the officer who commands that ship has received the King's commission. I know there is a single exception to that, with which I will deal in a moment, but in the British Navy, and all the world over, that is the meaning of the White Ensign and nothing else. So true is this that a number of vessels in the British Navy, such as harbour boats and others, which are not commanded by an officer carrying the King's commission, do not fly the White Ensign, but the Blue Ensign. The White Ensign is not a symbol of the British Admiralty nor necessarily of the British Navy. It is only a symbol of the King's commission. The single exception to which I referred is the Royal Yacht Squadron. In 1829, when the Duke of Clarence, subsequently William IV, was Lord High Admiral and a member of the Royal Yacht Squadron, he secured as a privilege to that club the use of the White Ensign. They ought not to have had it; but I do not think at that time the meaning of flags was as well understood, or their distinctive use appreciated, as it is to-day. There is no doubt that the Admiralty took very stringent steps subsequent to that period to prevent what had become a common practice of flying illegal colours. Nobody has taken away the White Ensign from the Royal Yacht Squadron; it is traditional now, and this exception has been allowed to stand; but with that exception the White Ensign has only the meaning, that the officer commanding the ship carries the King's commission."

Asked if the White Ensign of the Royal Yacht Squadron carried any letters on it, McKenna continued.

"It does not carry any distinctive mark. I give that as the single exception. It is not an exception of any great extent. The yachts of the Royal Yacht Squadron are never likely to be confounded with men of war; but still it is an exception and dates back a very long time. There is no other exception and frequently since 1829 both clubs and individuals have been prevented by the Admiralty from flying the White Ensign. I understand that it is common ground between us that every officer in the Imperial Navy, whichever fleet he may be in, whether the British, Canadian, Australian or New Zealand Fleet (if she had one), or the Cape Fleet (if she had one), will receive the King's commission, and if the officer receives the King's commission, he ought to be entitled, when he goes on board his ship and takes command, to hoist the White Ensign. It is the symbol that he does carry the King's commission. If you say no, the Blue Ensign is enough for you, the Admiralty can give the right to hoist the Blue Ensign, it is not the King's commission and it would be doing the very thing which I have understood not to be desirable - giving to the British Admiralty the appearance of a power which they do not claim and do not desire. Nationality ought to be denoted by the flags on the jack-staff, and they will be different I assume in each fleet. But the White Ensign ought to be common to all as the symbol that the navy is the Royal Navy.

Mr.Malan (Minister of Education, South Africa). "What exactly is the difference of opinion now as regards the flying of the flag, between the Imperial authorities and the Dominion authorities ?"

McKenna. "As I understand - and Sir Wilfrid Laurier (Prime Minister of Canada) could perhaps help me here - his representative Mr.Smith, K.C., who came over here, gave us to understand that your desire was that you should not have the White Ensign but the Blue Ensign, with a difference."

Mr.Brodeur (Minister of Militia and Defence, Canada). "On the question of the Blue Ensign, although we are not very particular about the Blue Ensign, we thought under the King's Regulations which are now in force in Canada, the only flag we would be allowed to fly would be the Blue Ensign because in the King's Regulations it is formally stated that 'All vessels belonging to the Dominion and armed, are obliged to carry the Blue Ensign.' This is what Mr.Smith was instructed to state."

McKenna. "I was looking at the question more from the point of view of the future than the past. Of course we should have to pass an Act, but in passing an Act we should contemplate the White Ensign as in future being the badge of the King's commission throughout the Imperial Fleet."

Brodeur. "He was instructed also to suggest whether it would not be possible to have the White Ensign with the arms of Canada in the centre of the Cross like the maple leaf, for example, or the Canadian arms. Perhaps there might be some objection to the Canadian arms being used because they are somewhat complicated; but those Canadian arms might be changed I believe. As you have stated the White Ensign represents the King's commission. The commissions to be given by the Dominions are to be given by the representatives of His Majesty. Perhaps it might be advisable in those circumstances that there should be something distinctive on the White Ensign to show that the commission that the White Ensign is supposed to represent has been given by the Dominion."

McKenna. "That is a difficulty. It is a question of the officers themselves. Your officers will go in our ships and our officers will serve in your ships, and there ought
to be interchangeability. I think that is common ground between us."

Brodeur. "Yes."

McKenna. "The officer serving in every case will have received the King's commission, whether directly from the King's own hand or signed by the hand of the Governor-General."

Brodeur. "I suppose the officer's commissions in the Admiralty, even the lieutenant's are signed by the King himself."

McKenna. "Yes ; every one."

Brodeur. "In our case they will not be signed by the King, but by the Governor-General, and in that case, as the commissions which are going to our officers will not be absolutely the same as the ones given to your officers, would it not be just as well to have something distinctive upon the flag ?"

McKenna. "Legally, it has precisely the same effect, and very often it will happen that our battleships will be commanded by your captains and you ships by our captains."

Brodeur. "Yes ; but when there is a British officer on our ship, the ship of course will also have the Canadian flag on the jack-staff."

McKenna . "Yes."

Brodeur. "We are speaking of the Blue Ensign which is going to fly astern. Do not you think in such a case it would be better to have a distinction made between the two, because commissions will not be given by absolutely the same authority ? Theoretically it will be the same. but in fact it will not be the same, because in your case the commission will be signed by the King himself, and in our case it will be the commission signed by the Governor-General."

McKenna. "It may not be so ; it may be a commission to one of our officers signed by the King. I think you are really getting, if I may so, into the notion of the White Ensign something of nationality which does not exist in it. Nationality is determined by the flag on the jack-staff."

Brodeur. "I will take precisely what you say in that respect - that the White Ensign represents the commission."

McKenna. "It is one commission whoever signs it, whether the King himself or his representative."

Brodeur. "As in both cases the commissions are not to be issued by the same person, would it not be advisable to have a difference ?"

McKenna. "Legally they are by the same person ; they are precisely the same in effect."

Mr. Herbert Asquith (British Prime Minister). "Suppose this case, which would be quite possible: a Canadian officer who has received his commission under the signature of the Governor-General, commanding a British ship. Do you suggest he should bring with him an ensign marked with a Canadian distinction."

Brodeur. "No, I do not think so in that case."

Asquith "Then take the converse case of a British officer who has received his commission signed by the King himself commanding a Canadian ship, what ensign is he to fly ?"

Brodeur. "I think that is a commission that will be represented by the White Ensign as the nationality of the ship itself."

Asquith. "I am supposing a Canadian ship commanded for the time being by a British officer who has got his commission signed by the King; what ensign do you suggest should be flown ?"

Brodeur. "I see a difficulty in such a case."

Asquith. "You see, if there is interchangeability it becomes very difficult to work it out, whereas the flag on the jack-staff would always indicate what is the nationality of the vessel. I understand that is the proposal."

McKenna. "It is."

Asquith "The Union Jack shows that it is a British vessel. I do not know what is the precise symbol you propose to have on the Jack-staff. Would not that be a more convenient way of indicating the nationality of the ship than by this difficult question of the commission ? I only throw it out as a suggestion."

Provisional Agreement.
82.C.1. The United Kingdom, Australian and Canadian Fleets to be sister members of the King's Navy, hoisting a common ensign, the White Ensign, as the symbol of the authority of the Crown, and each flying in addition its own distinctive flag forward on the jack-staff.
[National Archives (PRO) CAB 38/18. On microfilm item 40]

David Prothero

Use as a courtesy ensign

Should a visiting warship display a "courtesy ensign" at all and, if so, in the case of British waters should this courtesy ensign be the White Ensign (by analogy with the rule governing the use of the Red Ensign as courtesy by merchant ships) or should it rather be the Union Flag?
Merrick Bryan-Kinns, 8 September 2004

The answer is that in British waters a foreign warship would fly a White Ensign if they were to fly a courtesy ensign at all - it's not required by law that they do, but is always appreciated. Similarly vessels in government service, but not in their navy, should fly a Blue Ensign as a courtesy ensign. All other vessels should fly the Red Ensign. Of course warships and government vessels could fly a Red Ensign if they didn't have the appropriate White or Blue Ensign. It is an offence under the Merchant Shipping Act to fly a Union Flag from a ship, other than a commissioned ship of Her Majesty's Royal Navy. An appropriate course of action for an RN officer who notes a foreign vessel flying a Union Flag is to first check that no Admiral of the Fleet is visiting (the only possible reason for a foreign ship to be flying a Union Flag), and then present the vessel in question with an appropriately sized White Ensign to replace their erroneous flag, and explain diplomatically that they should not be flying the Union Flag.

As for the opposite case, a British warship in foreign waters, Queen's Regulations state that RN ships do not fly courtesy ensigns, but in true British fashion they sometimes do! They fly the naval ensign of the country they are visiting. In fact British warships even fly courtesy ensigns in Britain! When a warship is visiting a port in Scotland or Wales it is quite common for the ship to fly a saltire or red dragon as a courtesy ensign.
Graham Bartram, 8 September 2004

Dunkirk Little Ships

The Dunkirk Little Ships were those vessels taken up and used during Operation Dynamo in 1940. They may fly the White Ensign at the jack when at anchor or in port but not at sea when the normal ensign applies.
Steven Vincent
, 10 September 2002

See also: Dunkirk Jack

Royal Naval Reserve

Reported on the Royal Navy website:

Following a personal recommendation by the First Sea Lord, Her Majesty the Queen has graciously approved the presentation of the Sovereign's Colour for the Royal Navy to the Royal Naval Reserve (RNR) in recognition of their continuing support to the Regular Service. Commodore John Ellis, the Senior Reserve Officer, said: "This is a tremendous accolade for those who have served in the RNVR and RNR and for those serving today. The Wavy Navy (RNVR) which was amalgamated into the RNR in 1958, provided more than 80% of Naval Officers and Ratings in 1945 and that valiant spirit lives on, with more than 97% of today's RNR coming from a volunteer civilian background."

It is planned to combine the presentation of the Sovereign's Colour with a special parade in London to mark the centenary of the Naval Volunteer Reserves next year.
David Prothero, 21 August 2002

The Royal Naval Reserve does not have its own flag as such. RNR shore establishments fly the white ensign and the fast patrol boats used by the URNU are commissioned RN ships. The blue ensign may be used by RNR captains on merchant ships but I am not aware of any examples of commissioned ships being captained by RNR Officers. Territorial Army personnel are signed out of the TA and into the Regular Army when deployed on operations. Assuming parity with the RNR, and on that basis, I cannot imagine ever seeing an RNR Officer as Captain of a warship. Although theoretically possible (as RN ships fly both an ensign and pennant) the reference below confirms it is rarely seen in the Service.

A more succinct version of this, below (1), was taken from and the official version, bottom(2), was taken from

1. The Blue Ensign undefaced is worn by masters of vessels in possession of a warrant issued by the Director of Naval Reserves, and by the members of certain yacht clubs. Such warrants are issued to officers in the active or retired lists of the Royal Naval Reserve and the maritime reserve forces of other Commonwealth Realms and territories. The master must be of the rank of Lieutenant RN or above, and fishing vessels must be crewed by at least four other Royal Naval reservists or pensioners.
2. A variety of defaced Blue Ensigns are worn by Government vessels other than warships. Undefaced Blue Ensigns may be used by the holder of an Admiralty warrant which may be granted to the master of a merchant ship who is in the RNR. Blue Ensigns (defaced or undefaced) are also granted to some civil authorities and yacht clubs. It is rare to see an undefaced Blue Ensign in military service.
David Clegg, 3 May 2006

Royal Naval Auxiliary Service Senior Officer (Obsolete)

[Royal Naval Auxiliary Service Senior Officer] image by Miles Li

Source: H.M. Stationery Office (1958)
Miles Li, 19 June 2004

Dominion Navy Colours

Edwards (1953), page 145 and illustration of King's Colour Royal Navy on page opposite shows an illustration with a gold cord and gold tassels, while the text describes the Colour as having, "... red, white and blue silk cord and gold tassels." In fact the cord is blue and gold, and the tassels are blue and gold, and have probably never been otherwise. They are described as such in correspondence of 1925 in ADM 1/8972, and can be seen in colour photographs of the Colour being paraded at the return of Hong Kong to China in 1997.

Red, white and blue cord was used only on the "Service Colours", which had no Cypher or Crown, approved 5th March 1924, but replaced by the "King's Colour", approved 12th May 1925.

The Colours of Dominion Navies were the same as those of the Royal Navy except for the Royal Indian Navy, which had GRI [George Rex Imperator] as the Cypher, instead of GRV or later GRVI. They were taken to the National Defence Academy in Delhi in December 1950.
ADM 1/20767

A Colour was presented to the Royal Indian Navy in 1935. A problem arose in 1947 when the Navy was divided between India and Pakistan; which navy should have the Colour, supposing that either wanted it? The Colour was taken to Delhi on 10th August, five days before Independence, and lodged in the Defence Academy three years later.
David Prothero, 18, 20 June 2000

Corps of the Royal Marines

I don't know if it is the general practice, but a boat operated on the River Congo by 40 Commando, Royal Marines, flew the White Ensign above the Corps of the Royal Marines flag. The latter is officially, I think, the Royal Marine badge superimposed on a horizontally striped flag. The stripes (from the top) are: dark blue 4 units, yellow 1 unit, green 1 unit, red 2 units, blue 4 units. This represents the pattern of the Royal Marine stable belt on a blue flag. Blue for the maritime connection, yellow for the original uniform colour, green for the light infantry and red for the uniform colour in 1876. In the photograph of the boat, the flag has been simplified by omitting the badge and making all the stripes the same width.

David Prothero, 25 September 1999

This is the camp flag of Royal Marines headquarters, rather than the Royal Marines themselves. The Royal Marines do not have an ensign of their own and use the white ensign. Unlike the Royal Navy, they do have their own set of camp flags. 40 Commando's camp flag is unequal vertical stripes of light blue, dark blue, light blue. There are gold daggers on the light blue stripes and the Royal Navy badge on the dark blue stripe.

Graham Bartram, 27 September 1999

Each unit of the Corps of the Royal Marines has is own house flag and will fly this where they can. The Corps uses the Union flag when in Barracks, as a Commando in its home, on land base is working under the Army Act. This may change with the new amphibious force which is forming now jointly commanded by the Commandant General as the Military head and an Admiral as the amphibious head. The Corps uses the White Ensign on all her boats as they belong to the Navy, but as you say may fly a house flag alongside this. The Corps always uses a White Ensign on Naval Bases but may fly the Corps Colours (Blue, Red, Green, Yellow). You might also find that at Barracks like Lympestone, and Stonehouse the Corps might only use this flag in preference to either the Union flag or the White Ensign. 

Roger, Royal Marines, 26 December 2001

See also:

Just a note on the RMR flags on this web page (which stands for Royal Marines Reserves, as opposed to the full-time, professional units): they are obviously geographically based, with the London and the Scottish units using the London flag and the Scottish saltire respectively defaced with the badge of the Royal Marines. The other three units, Bristol, Mersey and Tyne, are vertical tribands with the RM badge on a red ground in the centre while the two outer bands have an element from the arms of the relevant city - the Liver bird for Mersey (Liverpool); the tower for Tyne (Newcastle upon Tyne) and the unicorns which are the supporters on the arms of Bristol.
André Coutanche, 14 November 2005

Note that these flags are unit "flags" and not "Colours". An example of a Royal Marines Regimental Colour can be seen at
T.F. Mills, 14 November 2005

Merchant Navy proposals

The term "merchant navy" dates from the Tudor period, when the term "navy" lacked the strictly military meaning it has now. The "merchant navy" was simply the nation's merchant fleet. John S. Ayer, 6 June 2000

The merchant navy is simply that. George V upgraded the Merchant Marine to the Merchant Navy in recognition of their services during WWI.

On 17th July 1918 the Naval Secretary wrote to the First Lord, "King sent for me yesterday and expressed a desire to signalise the war service of the Mercantile Marine by some distinctive recognition. He suggested a red St George's cross fimbriated white on the Red Ensign (see illustration by António Martins, 9 June 2000). This would not be for yachts, only bona fide merchant ships. The blue Ensign might be similarly altered with a red St George's cross fimbriated white." See illustration by António Martins", 9 June 2000.
ADM 1/8530/203.

Had these ever been introduced the dimensions would probably have been more like those of the later Civil Air Ensign. The Admiralty persuaded King George V that this was not a good idea and suggested a number of alternatives, one being an order that in future the Service was to be known as the British Merchant Navy. Later the Prince of Wales was appointed "Master of the British Merchant Navy and Fishing Fleets".

The term used before Merchant Navy, was Mercantile Marine, which had in general replaced the earlier term Merchant Service. The first commercial signal code introduced in 1817 was called, Captain Marryat's Code of Signals for the Merchant Service.
David Prothero and Andrew Yong, 6 June 2000

A Board of Admiralty meeting on 18th July 1918 concluded that there was no objection from a purely naval point of view, and appointed the Deputy Chief of Naval Staff and Naval Secretary to consider the historical aspects. On the same day the Head of the Legal Branch wrote that it would not conflict with any foreign flags, but would require amendments to the Merchant Shipping Act of 1894 if it was not to be for yachts, which had in many cases rendered good service. He added that it would also be necessary, if adopted to make fresh provision for badges in the fly of colonial ensigns, and that it was not clear how altering the Blue Ensign would recognise the service of the Merchant Service.

A Board meeting on 25th July advised against the proposals because:-

  1. The Red Ensign had been used by the Royal Navy and flown in many famous naval actions. The Red Ensign, as it was, conferred a greater honour on the wearer than would a modified ensign with no historical associations.
  2. The proposed modification symbolised only England .
  3. There would be a problem with badges of Public Authorities, Dominions and Colonies.
  4. It would be difficult to frame a definition of a merchant vessel entitled to wear the modified ensign, that would confine the honour to the ships on which H.M. desired that it should be conferred.
The Board suggested a red bordered Union Jack as jack in the bows, and a blue bordered Union Jack as jack for vessels that wore the Blue Ensign, but this was not, in the King's view, a sufficient privilege.

On the 12th August the Naval Secretary wrote that Captains of the Merchant Service had indicated that sentiment attached to the plain Red Ensign was so great that altering it would be an unpopular idea. Other ideas were floated including a white St George's cross on the Red Ensign, but by 20th August the Admiralty had decided that they were, "averse to any tampering with the Red Ensign".
David Prothero, 10 June 2000

Shifting the Colours

When did the Royal Navy adopt the "shift colours" procedure?

As far as the "colours procedure" is concerned, I can tell you why the practice started in the RN and roughly when, but not when (if ever) it was formalised? The wearing of an ensign at 'the peak' as opposed to an ensign staff at the stern, was introduced because of the replacement of a loose-footed spanker on the mizzenmast by a gaff sail with a horizontal boom which projected over the taffrail (and would have knocked it off its staff when the ship was underway). Whatever date the process started, it can confirm that it was not complete (in major ships at least) by 1805, since some of the ships which fought at Trafalgar carried their ensigns at the peak and some from a staff.

With the introduction of 'mastless ironclads' into the battle fleet - from the 1870's onward - the 'necessity' disappeared as fast as new ships could be built to replace the steam-assisted sailors, but the practice of an ensign on a staff when moored and from the peak at sea appears to have continued because of 'custom and practice'? With this introduction the practical reason for not flying a jack whilst underway ceased as well, and I wonder if the RN also took to flying them underway during the years before 1900?
Christopher Southworth, 1 October 2004

From my own experience as a sea-going commanding officer and 35 years of Naval service, the following observations on this subject. In modern navies the shifting of the colours from ensign staff to the masthead gaff was for the purely practical reason that leaving the ensign staff up (the reason for shifting the ensign in the first place is to strike the ensign staff) would interfere with the operation of aircraft (helos) and armament (turrets and ASW mortars). The only ceremonial involved was that the striking of the ensign at the ensign staff was not to be done before the ensign at the gaff was close-up. The ensign at the gaff was usually a storm ensign for obvious reasons. When in company, this evolution might be ordered by signal by the Officer in Tactical Command (OTC).

It was also the practice in our [i.e. South African] Navy (issued as an instruction after one ship managed to shoot its own jackstaff to smithereens) to strike the jackstaff as soon as the ship has left harbour. To protect it from foul weather also, even when no shoots are scheduled, the jack staff is struck and lashed on the forecastle as soon as the ship is at sea.

I have never heard of the jack being flown whilst underway in modern navies (except of course for ceremonial reasons such as dress ship days or conveying a head of state). The hoisting and lowering of the jack during the day (that is other than at the ceremony of Sunset) is today in fact a signal. The jack is hoisted as soon as the anchor is let go or the first line goes ashore when coming alongside. Similarly it is struck as soon as the anchor is up and down, i.e., broken loose from the ground, or the last line is cast off from the quay. In close waters the lack of a jack flying in a warship (and to some degree in merchant vessels) is thus a signal to all in the vicinity that the ship is underway, or when it is flying, that the ship is attached to the land in some way.

I suspect that these practices also apply in the British Royal Navy for the same reasons.
Andre Burgers, Cape Town, 1 October 2004

I don't think that, in general, it ever has been officially changed. Photographs show that RN ships normally leave the ensign on its staff at the stern, and only occasionally fly it from the mast of a ship with only one mast. Ships with two masts hoisted the ensign on a gaff at the after mast. Some ships, destroyers/frigates/ corvettes in WW2, and current mine counter-measure ships had/have a stub mast on the superstructure between the funnel and the stern on which the ensign is hoisted, sometimes on a gaff. Hoisting the jack in harbour was not made an official requirement until 1920, and before that, in some places and circumstances, was prohibited.

1844 Queen's Regulations; "... and with Union Jacks at bowsprit ends when it shall be thought proper to display them". It was not until 1913 that "jack staff" replaced "bowsprit-ends".

1907 Plymouth Station Order Book; "Ships refitting, coaling, giving general leave, or otherwise out of routine are to hoist ensign only, the jack when hoisted signifying that the ship is in full routine, and ready for the service for which she was commissioned."

1920 King's Regulations; "Union Flag is to be worn at the jack staff by all ships when in harbour, or under way and dressed with masthead flags." It is thought that this amendment changed a long-standing custom into an official instruction..

David Prothero, 2 October 2004

Kings Regulations (1808)

The following references to flags appear in, "Regulations and Instructions Relating to His Majesty's Service at Sea. Established by His Majesty in Council 1808."

Flag Officers.
XXII. "A Flag Officer is never to allow the squadron to carry the Colours hoisted at sea nor to hoist them in blowing weather in harbour."

XXVI. "If any Flag Officer shall die when on actual service his flag shall be lowered to half mast and shall continue so until he is buried."

The Captain.
XX. "He is to be very careful of the ship's Colours which are never to be hoisted at sea except on meeting with other ships, or for the purpose of being dried; nor are they to be hoisted in harbour in blowing weather."

Of Colours.
I. That Flag Officers are only to carry their own rank flag.

II. That when two Flag Officers of the same rank serve together the Commander-in-Chief may order either to carry such other flag as he sees fit.

III. About boat flags for admirals.

IV. "Packets employed by the Post Office and having a commander appointed by a commission from the Admiralty are permitted to carry a Red Ensign, a Jack, and a Pendant, but no other Pendant."

V. "Merchant ships are to carry a Red Ensign with a Union Jack in canton, and White Jack with Red Cross, commonly called St George's Cross, passing quite through it."

VI. "Private Commissions or letters of Marque or letters of Reprisal are to carry the same Ensign as merchant ships, and a Union Jack with a broad red border at the end and foot thereof."

VII. "Ships employed by Public Offices carry the same Ensign and Jack as ships having letters of Marque except that in the fly of the Ensign there shall be described the seal of the office to which they belong."

VIII. That foreign ships were not to be allowed to ride in ports and roads with false colours.

David Prothero, 18 February 2005

Decommissioned ships preserved as memorials

"Belfast" in London, "Haida" in Toronto, and "Sackville" in Halifax, Nova Scotia, have I think always been allowed to fly the White Ensign. "Plymouth" and "Bronington" both in Birkenhead used to fly a White Ensign, the fly defaced with the words 'Historic Warship', but now have permission to fly the undefaced White Ensign.
HMS "President" flew the White Ensign while she was the drill ship of the London Division of the RNVR/RNR, from 1904 until 1988, when the Division moved to premises at St Katherine's Dock, below Tower Bridge. She was the screw sloop formerly HMS "Buzzard" until 1922, when the name was transferred to the sloop formerly HMS "Saxifrage". She was joined by a sister ship HMS "Chrysanthemum" in 1939. Both ships were sold in 1988. HMS "President" should originally have flown the Blue Ensign. It was, I think, her unchallenged use of the White Ensign that set a precedent, and led to the White Ensign becoming the official ensign of the RNVR in 1924.
David Prothero, 9 August 2005