The Parliament of the United Kingdom on occasions introduces legislation that is extended to the islands, normally by the use of Orders in Council.

[9] Section 19 of the Lloyd's Signal Stations Act 1888 contained a definition of "British Islands".

On 27 March 1923 an Order in Council was made changing the default statutory interpretation of various expressions, including "British Islands", "United Kingdom", and "Ireland"; they would be interpreted within the British Islands as excluding the Irish Free State, but interpreted elsewhere in the British Empire as including the Irish Free State.

[13] Section 28(ii) of the Interpretation and Common Form Ordinance, 1903 of the Seychelles contained a definition of "British Islands".

[14] Section 13(3)[15] of the Foreign and Colonial Parcel Post Warrant 1897 (SR&O 1897/721) and section 6(2)[16] of the Foreign and Colonial Post (Insured Boxes) Warrant 1908 (SR&O 1908/1313) refer to "the law of the British Islands".