Call for MPs to approve 'unelected' prime ministers
Parliament should "approve" a change of prime minister between general elections before a new leader can officially take power, MPs have said.
Staging a vote in the Commons would boost accountability and show a new PM had the explicit confidence of MPs, the Political Reform Committee said.
Two of the last four prime ministers took power without a general election.
The committee also called for changes to the machinery of government to codify the prime minister's powers.
In a wide-ranging report, the cross-party committee also discussed the pros and cons of a prime minister being directly elected while acknowledging this is unlikely to happen in the "near future".
There have been 15 changes of prime minister in mid-term since 1902, most recently in 1990 when John Major replaced Margaret Thatcher and in 2007 when Gordon Brown succeeded Tony Blair.
Mr Brown considered calling a snap general election at the time but rejected the idea.
The committee said ministers should consider whether Parliament should have a role in approving prime ministers who come to power in such circumstances.
A so-called "investiture vote" could be held, they suggested, to signal Parliament's consent before an individual was officially asked to form a government by the sovereign.
Only once in the last 100 years - when Winston Churchill took over from Neville Chamberlain in 1940 - has the Commons held an immediate confidence vote in the new government upon a mid-term change of leader.
The committee said such a vote was "perfectly possible" and would allow the Commons to express their opinion on an individual "for whom the public did not feel they had voted".
"The vote would result in a clear line of accountability and would make it explicit that the prime minister commands the confidence of the majority of the House of Commons," it said.
The principle could be extended to all prospective prime ministers, it added, although it acknowledged that it was "difficult to imagine" a situation in which the Commons did not vote to support the leader of a party which had won a parliamentary majority or was the largest party in a proposed coalition.
In such a situation, the committee suggested that the prime minister in waiting would be known as prime minister designate until their appointment had been voted on by the House and approved by the monarch.
"The prime minister designate would be able to perform all the main functions of the prime minister, including appointing ministers and instructing civil servants but would not take the title of prime minister until he or she had been confirmed in the post," it added.
More widely, the committee said that while the cabinet and Parliament served as a "check and balance" on the prime minister of the day, No 10's powers had increased in recent decades and were still not well defined.
The use of so-called "prerogative" powers should be laid down in statute, it said, while the Cabinet Office should be renamed the Department for the Prime Minister and the Cabinet to ensure greater understanding and transparency about the prime minister's involvement in policy making.
"Without any clear definition, the PM's role and powers have been able to grow and add to the massive over-centralisation of Britain," Labour MP Graham Allen, who chairs the committee, said.
"Our inquiry came up with some practical reforms for improving accountability but we are also opening up a discussion on some more radical reforms with the hope of provoking debate about how the role and powers of the prime minister should change in the years to come," he added.