The government of the United Kingdom is responsible for the defence of, and foreign relations of, the Channel Islands - i.e. the Bailiwicks of Guernsey and Jersey. How did this arrangement come about?

Was there a specific agreement/decision/event or did it just develop over the centuries with the development of international diplomacy and the increasing sophistication, and geographic reach, of military hardware?

The history of this issue it not covered in Wikipedia. It merely states that the current arrangement is that defence is a UK government responsibility, without further comment or history. There is a general history of the Channels Islands and how the crowns were united - the Channel Islands were part of Normandy before the Norman conquest of England in 1066 - but nothing about the history of the English, British, or UK government having extra-jurisdictional defence responsibilities.

I have found this briefing paper from the UK government setting out the current position but have been unable to find anything on the history of this particular point.

Obviously it makes practical sense for the UK to be responsible for the defence of the Channel Islands but my question is about the how in terms of the crystallisation of a constitutional principle.

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    This may be on topic here, but it might also be better as a question for Historyians
    – James K
    Nov 3, 2021 at 20:18
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    Methinks this would be much better on History. Nov 3, 2021 at 23:15
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    I’m voting to close this question here because it was crossposted on history stack exchange. Please note that crossposting on stack exchange is not allowed. A question should only be posted on the site where it is most on-topic on.
    – Philipp
    Nov 9, 2021 at 8:20
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    It was cross posted at the specific suggestion of users as can be seen from the comments above. Also History SE seem to not like questions on constitutional history for some reason so if cross posting is not allowed the it would be better if it stayed on Politics SE rather than History SE
    – Nemo
    Nov 9, 2021 at 8:35
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    I've voted to reopen this question. The political status of the channel islands and how that status compares to that of other territories (or doesn't) is certainly on topic, and the nature of that status is impossible to discuss without considering the history of the channel islands and the UK.
    – phoog
    Nov 9, 2021 at 10:59

2 Answers 2


Short Answer

The formalistic legal theory is that the King/Queen of England (as Duke of Normandy, 133 years before actually gaining that title) gained ownership and control of the Channel Islands, but chose to administer these islands directly, rather than as a political subdivision of England or the U.K.

But, since the military and foreign service of the U.K. had an obligation to serve the needs of the King/Queen of England (and all sorts of other places personally united in the same person), the King/Queen of England gave it that responsibility which economies of scale made inefficient to have the Channel Islands provide for themselves. This arrangement was then continued in 1926 when the personal unification under the same monarch of the various constitutional monarchies and dependencies into a single regime called the British Empire, was superseded by a conception that there were distinct countries, each of which happened to have the same monarch, which came to be known as the British Commonwealth.

Long Answer

How did this arrangement come about?


In 933, the islands were granted to William I Longsword by Raoul King of Western Francia and annexed to the Duchy of Normandy. In 1066, William II of Normandy invaded and conquered England, becoming William I of England, also known as William the Conqueror. In the period 1204–1214, King John lost the Angevin lands in northern France, including mainland Normandy, to King Philip II of France, but managed to retain control of the Channel Islands. In 1259, his successor, Henry III of England, by the Treaty of Paris, officially surrendered his claim and title to the Duchy of Normandy, while the King of France gave up claim to the Channel Islands, which was based upon his position as feudal overlord of the Duke of Normandy. Since then, the Channel Islands have been governed as possessions of the Crown and were never absorbed into the Kingdom of England and its successor kingdoms of Great Britain and the United Kingdom.

The distinction between a military and diplomatic corps that owed a duty to the King/Queen of England as an individual in whatever capacity the monarch saw fit, and a military and diplomatic corps that was a bureaucratic arm of a particular national government among many for which the King/Queen of England was the monarch, really doesn't come into being as a practical matter, until the early 19th century (quoted below) when the executive branches of the British Empire came to be governed more or less exclusively by the prime minsters of the respective national governments (a.k.a. "Dominions") or Crown dependancies, rather than being personally operated non-symbolically by the monarch or by a Governor-General or Bailiff appointed by and serving at the pleasure of the personal and individual will of the monarch.

But, this transition cannot fairly be described as an all or nothing affair that happened at a single moment with a single legislative enactment.

From 1811 to 1820, George III suffered a severe bout of what is now believed to be porphyria, an illness rendering him incapable of ruling. His son, the future George IV, ruled in his stead as Prince Regent. During the Regency and his own reign, the power of the monarchy declined, and by the time of his successor, William IV, the monarch was no longer able to effectively interfere with parliamentary power. In 1834, William dismissed the Whig Prime Minister, William Lamb, 2nd Viscount Melbourne, and appointed a Tory, Sir Robert Peel. In the ensuing elections, however, Peel lost. The king had no choice but to recall Lord Melbourne. During William IV's reign, the Reform Act 1832, which reformed parliamentary representation, was passed. Together with others passed later in the century, the Act led to an expansion of the electoral franchise and the rise of the House of Commons as the most important branch of Parliament.

The final transition to a constitutional monarchy was made during the long reign of William IV's successor, Victoria [whose reign ended in 1901].

By the time that the transition of the military and foreign service from a personal set of subordinates of a monarch to divisions of national governmental organizations took place, from about 1811 until 1901, the Channel Islands had shared its military and foreign affairs bureaucracies with the U.K. for more than eight hundred years in the prior arrangement when these bureaucracies were unified under the person of the monarch.

As the military and foreign service increasingly came to be seen as reporting to the U.K.'s prime minister rather than truly reporting to the monarch, the dissonance between the military and foreign service being U.K. agencies and these bureaucracies serving the Channel Islands emerged as something that a logical mind would be troubled by, and so the need to formalize this legally to expressly allow this arrangement which was not logically obvious in the new order arose.

One key moment that solidified this development which had been coming into being piecemeal for about a century at the time, and was largely a fait accompli by the time that it was formally recognized, was the Balfour Declaration of 1926 which ended the notion of all nations with the same monarch being at the highest conceptual level of abstraction, the same country:

Prior to 1926, the British Crown reigned over the British Empire collectively; the Dominions and Crown Colonies were subordinate to the United Kingdom. The Balfour Declaration of 1926 gave complete self-government to the Dominions, effectively creating a system whereby a single monarch operated independently in each separate Dominion. The concept was solidified by the Statute of Westminster 1931, which has been likened to "a treaty among the Commonwealth countries".

The countries that shared the King/Queen of England formally known as the British Empire (pre-1926), at this time came to be known as members of the British Commonwealth.

So, formal legislative recognition of the longstanding practice of having the U.K. military and foreign service take care of the affairs of the Channel Islands, an arrangement which abrogated the general rule that each nation or dependencies provided its own governmental services, was probably only enacted in connection with this reconceptualization of the British Empire from 1926-1931.

Any subsequent legislation or regulations or practices merely codified the pre-existing practice. But I am not enough of a technical expert to point to specific enactments that codified this practice.

From 1940-1945, the Channel Islands were occupied by the German Army, after the U.K. evacuated many people because it was incapable of military defending them in 1940. Military defense of the Channel Islands was part of the larger Allied war effort in World War II and there were no foreign affairs to be conducted when the islands were under harsh German military rule.

The legal and political details are described in detail here. The legal basis of this arrangement is currently spelled out piecemeal in a variety of different pieces of local and U.K. legislation. A couple of the more important enactments are that:

Under the UK Interpretation Act 1978, the Channel Islands are deemed to be part of the British Islands, not to be confused with the British Isles. For the purposes of the British Nationality Act 1981, the "British Islands" include the United Kingdom (Great Britain and Northern Ireland), the Channel Islands and the Isle of Man, taken together, unless the context otherwise requires.

Incidentally, this arrangement is not unique to the Channel Islands. It is the arrangement that is in place for essentially all self-governing colonial jurisdictions of both the U.K., and of almost all other Western countries. This is what France has done, for example. It is also what is done by the U.S. in the cases of Puerto Rico, the U.S. Virgin Islands, Guam, and the U.S. Marinara Islands (and was previously the case in the Philippines when that was a U.S. dependency).

Indeed, in the case of a territory having democratic domestic self-government, having one's military and foreign affairs handled by another nation in which one does not have a political say is a core part of the concept of a territory as a political dependency of the country in charge of its military and foreign affairs.

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    @Nemo In English history, events often formally occur long after they really happen.
    – ohwilleke
    Nov 3, 2021 at 19:24
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    @Nemo substitute "empire" for "commonwealth." Also consider the relationship of Scotland with England and of Ireland with Great Britain before the formation of Great Britain and the United Kingdom: they were distinct kingdoms that happened to have the same person occupying the throne. The Channel Islands' status arose similarly, but they were never subsequently united with England nor the UK in the same way as Scotland and Ireland were.
    – phoog
    Nov 3, 2021 at 21:39
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    @phoog The answer seems to be concentrating on British colonies in the Imperial period and their evolution into being independent Commonwealth countries, but the Channel Islands were never British colonies and are not members of the Commonwealth.
    – Nemo
    Nov 3, 2021 at 21:46
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    @Nemo legally speaking, sure, but for practical purposes they have a very similar status to colonies, which is recognized in their status as "crown dependencies."
    – phoog
    Nov 3, 2021 at 21:51
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    @Nemo which the answer covers: first personal union, then the development of constitutional monarchy in tbe 19rh century leading to the present state of affairs.
    – phoog
    Nov 3, 2021 at 22:13

It became inevitable because of developments in international law

The reason, or at least part of the reason, seems to be developments in International Law following the treaties known as the Peace of Westphalia (1648).

Neither England nor the Channel Islands were parties to the treaties but the treaties seem to have been the starting point for the development in International Law of the modern idea of states and the result that, in International Law, the United Kingdom is a state whereas neither Bailiwick in the Channel Islands is a state. In the Barclay Brothers (No 2) case the UK Supreme Court commented:

Nevertheless, the Bailiwicks are not independent states in international law. The United Kingdom Government is responsible for their international relations and for their defence. But it is the practice to consult the Island authorities before entering into any international agreement which would apply to them. The UK has also undertaken not to act internationally on behalf of a Crown Dependency without prior consultation; recognises that their interests may differ from those of the UK (especially in relation to the European Union, of which the Islands are not members) and so it may have to represent them both; and supports the principle of the Dependencies’ further developing their own international identities...

If the Channel Islands came to be regarded as falling on the non-state side of the state/non-state division as that developed in international law following the Peace of Westphalia, it then would follow that the Bailiwicks could not act formally for themselves on the international stage in, for example, signing international treaties.

Up until around the time of the 1926 Balfour Conference a majority of treaties were entered into in the name of Her/His Britannic Majesty. After then treaties were often entered into by the relevant Commonwealth countries who were independent members of the League of Nations and also by the King in respect of those who were not.

But in time this practice ceased and so you have most treaties entered into by the United Kingdom alone. This would have highlighted the fact that the United Kingdom was the contracting party even where the subject matter of a treaty was, or included in some way, the Channel Islands.

If that was the practical reality on the international stage, the UK was obliged to represent the Channel Islands in formal foreign relations and that creates, by virtue of necessity, an internal constitutional convention that the UK is responsible for the formal international affairs of the Channel Islands.

From that it must have followed that the UK government was also responsible for the defence of the Channel Islands since the conduct of international relations always has defence in the background - the extent to which a state is willing to take positions in international relations which might ultimately give rise to a military threat from other states depends, among on things, on its defence capabilities and its willingness to deploy them.

So the constitutional convention that the UK is responsible for the defence of the Channel Islands would appear to have emerged gradually along with the convention that the UK is responsible for foreign affairs. They are an internal constitutional response to the Peace of Westphalia but did not need to be precisely defined until the period following the 1926 Balfour Conference.

Comment on ohwilleke's answer ohwilleke's answer regards former British Colonies (now Commonwealth countries) on the one hand, and the Channel Islands, on the other hand, as being in essentially the same position. I am not convinced that this is so. There may be a superficial resemblance in that the UK is still responsible for the defence of many small Commonwealth Countries but the way this has arisen is quite different. These colonies were completely controlled by the UK and the fact that the UK is now responsible only for defence/foreign relations is because that this is all that is left after all other powers over the colony have been relinquished. By contrast England/Great Britain/the UK never had any control over the Channel Islands - the crowns were united in 1066 but that is all.

So in the case of the former colonies, UK responsibility for defence/foreign affairs is what remains after other powers have been relinquished, but in the case of the Channel Islands, UK responsibility for defence/foreign affairs has, somehow, been extended to the islands. So a different explanation is needed, it seems to me.

William Blackstone, writing in Vol. 1, Commentaries on the Laws of England (1765), draws a clear distinction between the Channel Islands and British colonies.

With regard to the other adjacent islands which are subject to the crown of Great Britain, some of them (as the isle of Wight, of Portland, of Thanet, etc.) are comprised within some neighboring county, and are therefore to be looked upon as annexed to the mother island, and part of the kingdom of England. But there are others which require a more particular consideration. And, first, the isle of Man is a distinct territory from England, and is not governed by our laws: neither does any act of parliament extend to it...

The islands of Jersey, Guernsey, Sark, Alderney, and their appendages, were parcel of the duchy of Normandy, and were united to the crown of England by the first princes of the Norman line. They are governed by their own laws, which are for the most part the ducal customs of Normandy, being collected in an ancient book of very great authority, entitled, le grand coustumier. The king's writ, or process, from the courts of Westminster, is there of no force; but his commission is. They are not bound by common acts of our parliaments, unless particularly named. All causes are originally determined by their own officers, the bailiffs and jurats of the islands; but an appeal lies from them to the king and council, in the last resort.

Besides these adjacent islands, our more distant plantations in America, and elsewhere, are also in some respect subject to the English laws. Plantations or colonies, in distant countries, are either such where the lands are claimed by right of occupancy only, by finding them desert and uncultivated, and peopling them from the mother country; or where, when already cultivated, they have either gained, by conquest, or ceded to us by treaties...

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