Deputy Prime Minister of the United Kingdom as to the absence of a formal post of Deputy Prime Minister in Britain's uncodified constitution. Theoretically the sovereign possesses the unrestricted right to choose someone to form a government following the death, resignation or dismissal of a Prime Minister. One argument made to justify the non-existence of a permanent deputy premiership is that such an office-holder would be seen as possessing a presumption of succession to the premiership, thereby effectively limiting the sovereign's right to choose a prime minister. However, only two Deputy Prime Ministers have gone on to become Prime Minister. Clement Attlee won the 1945 general election
Council of Civil Service Unions v Minister for the Civil Service While the use of the Royal Prerogative for national security reasons is considered outside the scope of the courts, most other uses of the Prerogative are now judicially reviewable in some form. The GCHQ case also confirmed that non-legal conventions might be subject to "legitimate expectation". A convention would not have usually been litigible, and it was necessary for the court to demonstrate that it was in the present case: such a rule had been established in respect of Cabinet conventions in "Attorney General v Jonathan Cape Ltd". Although the court ruled against the union, it was accepted that the