British politics is locked in a reshuffle culture that undermines the way the country is governed, according to a Commons committee.
Months of speculation ahead of a shake-up creates "a kind of paralysis" within government that is followed by an "inevitable delay" in ministerial effectiveness once it has taken place, MPs said.
They called for fewer reshuffles and a new expectation that Secretaries of State remain in post for the duration of a parliament while their juniors should generally serve at least two years.
The Political and Constitutional Reform committee praised Prime Minister David Cameron, who is widely expected to carry out a reshuffle in the coming months, for the "comparative restraint" he has shown in moving round his ministers.
But it raised concerns about the high turnover of Whitehall's most senior civil servants since the coalition took power. Among the permanent secretaries to resign since the general election are former civil service head Lord O'Donnell, Dame Helen Ghosh from the Home Office and Jonathan Stephens from the Department for Culture, Media and Sport.
"Continuity in the senior civil service is an important factor in departmental stability, along with continuity of ministers," the impact and effectiveness of ministerial reshuffles report said.
"We are concerned by the recent high turnover among permanent secretaries."
The committee said reshuffling is sometime unavoidable as a result of resignations, illnesses and deaths but insisted no shake-up should take place without a good reason.
"Reshuffles have become a habit in the UK and altering this will require a change of mindset," it added.
Regular changes make it more difficult for Parliament to hold the responsible minister to account for policy failures because they may have been moved from their post before problems with a decision emerge, MPs said.
They called for outgoing ministers to hand over directly to their successors and suggested that a compulsory training programme, along with annual appraisals, should also be introduced.
The committee also said it had seen no evidence that serious consideration had been given to cutting the number of ministers in light of devolution to Northern Ireland, Wales and Scotland.
Committee chairman Graham Allen said: "Reshuffles are damaging to the effectiveness of individual ministers and of government as a whole.
"They also hinder Parliament's ability to hold government to account. In the UK, we've got used to having reshuffles every couple of years, but other countries manage very well without them. Every time there is a reshuffle, it is proceeded by months of speculation about who will move where, which in itself causes a kind of paralysis within government.
"I welcome the fact that the current Prime Minister has had only one reshuffle. I hope our report will encourage future prime ministers to follow his example. We call for Secretaries of State to be left in post for the length of a Parliament. Taken together with the advent of fixed-term Parliaments, this should enable them to make a real difference.
"We heard a great deal of evidence about the irrationality of reshuffles. We recognise that, at their heart, reshuffles are political events. But our report makes some recommendations to improve training, feedback and handovers, which are aimed at making the process more rational."
A spokeswoman from the Institute for Government, the organisation the committee recommends should help develop ministerial inductions and appraisals, said: "We welcome the committee's report on Cabinet reshuffles.
"Most recent prime ministers have reshuffled too frequently, chopping and changing their teams for the sake of short-term, often illusory, political gain and often at the expense of stable and effective political leadership.
"When reshuffles do take place, there should be a better planned handover process and incoming ministers should be provided with training and development support to enable them swiftly to get up to speed with the demands of the job.
"We are delighted to assist, as the reports recommends, in providing induction and development support after a reshuffle and when a new government is formed".Suggest a correction