The Attorney General sought injunctions to restrain the publication of the diaries of a former Cabinet minister.
A court can restrain publication of Cabinet material only where there is breach of confidence or it is in the public interest to do so to protect collective Cabinet responsibility. But this lapses with time according to the circumstances of each case. Applying this principle, sufficient time had lapsed to allow publication.
The Privy Council had to decide whether the UK Parliament could legislate for Southern Rhodesia, following the Unilateral Declaration of Independence.
A constitutional convention, however important, can have no legal effect to limit the legislative supremacy of Parliament.
This was an attempt to question the legality of the Canada Act 1982 in the British courts by a minority group within Canada. It was suggested that the convention that the UK Parliament should not legislate for Canada except with its consent might by formal recognition or by long acceptance have crystallized into a law.
Conventions cannot become part of the common law in the same way that customs are capable of doing.
In 1980 the Canadian Federal Government devised a package of constitutional reforms which were opposed by a majority of the provinces. The Supreme Court of Canada was asked to decide whether the Federal Government could go ahead with the scheme without the consent of the provinces.