Nick Clegg could serve as prime minister for a month after the general election until a new coalition is formed, a senior Lib Dem MP has suggested.
Former defence minister Sir Nick Harvey said unlike the 2010 coalition deal which was hammered out in just five days, any negotiations after this May's poll should take much longer.
In an interview with The Huffington Post, Harvey said this would require an "interim government" to be in place while political parties haggled over the formation of a new administration.
Harvey said as the incumbent, David Cameron should remain in Downing Street until a deal was struck. But that if the Conservative leader "was so fucked off" he wanted to leave then there was "no reason" why Clegg could not fill the role - assuming of course the deputy prime minister keeps his seat.
The veteran Lib Dem MP also said it would be "much harder" for the party leadership to convince its members to vote for another coalition and said he would be "certainly willing" to argue in favour of the party staying out of power.
Harvey, who predicted Ed Miliband would wake up on 8 May with the most MPs, also said the Lib Dems could fill half its ministerial positions in a future coalition with members of the House of Lords - if the party sees its number of MPs reduced to around 30.
He was speaking to HufPost following the publication of his book, After the Rose Garden, which examines the mistakes the Lib Dems made during the 2010 negotiations with the Tories.
"I personally think that they should take at least a month," Harvey said when asked how long any negotiations should last. "And I think that what you need during the course of that month is some sort of interim government. Where you've got a prime minister and home secretary and a chancellor. And maybe a deputy prime minister. I don't think it is right to appoint a government of 121 members until such time as you have a deal. If the deal is going to take a month, you could just appoint a government of eight or ten ministers.
"It should be the prime minister's last duty to remain at the desk until such time as as somebody has gone and kissed the Queen's hand and accepted the burden of office.
"The problem in 2010 was that Brown was taking flack. People were saying he is clinging on by his fingernails. That was putting him in an impossible position. I am not surprised that he walked when he walked."
The Sun famously savaged Brown for failing to leave Downing Street as soon as the votes were counted, despite the absence of a new government. 'Squatter, 59, holed up in No. 10,' the paper complained.
Harvey said: "If it was a Lib-Lab discussion going on, Cameron ought to remain in office. If he was so fucked off he didn't want to, I would understand that in human terms. But I think personally it would be a dereliction of duty, I think he should remain there until it's done.
"Failing that of course, Nick Clegg is the deputy prime minister. There is no reason why he couldn’t act up for a few weeks."
The MP for North Devon, who was unexpectedly fired from his job as armed forces minister by Clegg in September 2012, said Miliband could also serve as interim prime minister during the negotiation period if he was able to convince the Queen that Labour was involved in a "serious discussion" with other parties to form a government.
Sir Nick Harvey, the former defence minister, has spent time examining the pitfalls of coalition
With almost exactly three months to go until the election, polls suggest Britain could be heading for another hung parliament. And despite the cratering of its support, the Lib Dems may once again be the kingmakers.
Harvey has said the key mistake made in 2010 by his party was not to insist on having a minister in every department. Under his formula this would mean the Lib Dems would have 30 ministers in any post-2015 deal. However it is entirely likely the party may struggle to see 30 MPs elected.
Harvey does not see this as a problem."I don't see why if we’ve got 33 MPs we deserve any less than if we've got 57, if the way we are using them is making the government possible," he said.
"If the number of MPs we're offering into the equation is the difference between there being a government and there not being a government then our core demand should be a minister in every department. If you are asking me will we have the personnel to staff a minister in every department, there is no reason ministers cant be peers. We have over 100 Lib Dem peers, many of whom are very high caliber.
"Actually if we had 33 MPs and 31 government posts, there would be a lot of sense in bringing peers in to fill probably half of the government posts. Otherwise the ministers in the Commons wouldn’t have any backbenchers behind them to support them on committees etc.
"There will be some MPs who wouldn’t want to serve as ministers and there would be some who would be new. You can't tip them straight in as ministers. You need a backbench actually. It may only be a small backbench but you would need a backbench. And therefore with all the wealth of the experience we've got in the Lords, that’s the obvious answer to the personnel shortfall."
It is often taken as read that if the Lib Dems are offered the chance to form another coalition, with Labour or the Tories, they will take it. However Harvey is less sure. "It will be much harder to convince the party again," he said. "We have lost a third of our members, we've lost almost half our councillors, we are going to lose a lot of our share of the vote, we are going to lose some parliamentary seats, most people think. We have paid an awful price for it. I don't know whether the party will sign up to another coalition but what I do know is there will be a really meaningful debate and you won't get a situation where 1,500 souls gather at the NEC and only ten rebel."
In 2010, Clegg convinced an overwhelming majority of his party members to back the deal with Cameron during a special party meeting at Birmingham's NEC centre. Former leader Charles Kennedy was the only MP not to vote in favour - and he chose to abstain.
Harvey, who experienced two years working under two Conservative defence secretaries in the Ministry of Defence, was himself reticent about signing up to another coalition. "I wouldn’t rule it out," he said when asked if he would vote for another coalition. "We would have to wait and see what the arithmetic looked like, what the deal looked like. But I would certainly be willing to turn our back on the prospect. But I'm not dead set on that. Let's wait and see what's on offer."
First elected to parliament in 1992, Harvey's politics are closer to Labour's than the Conservatives. "Philosophically, yes," he said when asked if he would prefer a coalition with Miliband than another with Cameron. However he said there were practical problems.
"I don't underestimate how difficult it would be. I don't underestimate how tribal the Labour Party is by comparison with quite a pragmatic Tory party. I don't sense that Labour are working on this at all. I think they are just going for a victory on their own. I don't think they have opened up communications channels. I don't think they have game planned how they would respond to the hung parliament scenario," he said.
"If they are anywhere near as ill-prepared or as negative in their attitude in 2010, when Harriet Harman was more or less telling Chris Huhne to go off and be a glorified research assistant when he was sitting on the offer of a cabinet seat from David Cameron, they will just need to really up their game drastically, if they are serious about wanting this as an option."
With the election on the horizon, senior Lib Dems are already manoeuvring for the chance to succeed Clegg whenever it is he steps down as leader. But Harvey warned Labour against trying to demand the deputy prime minister's head as part of any deal. If anything, he said, such a demand would unite the party behind Clegg.
"It's going to be much more a partnership of equals," he said of any future deal. "And If you think you are going to get that off to a good start by telling us on day one who our leader can or can not be, I don't think you are hearing what we are saying.
"The anti-Clegg thing is all sort of irrational. Labour have chosen to demonise him since 2010, particularly over student fees. Even Lib Dems who aren't sympathetic to Clegg would feel we had to unite as a party and stand shoulder to shoulder with him. The larger party can't tell us who our leader is."
In 2010, Clegg told Gordon Brown that he would have to resign as Labour leader if any Lib-Lab deal was to work. Many Labour MPs would like to take revenge on Clegg for that. However Harvey said it is not a fair comparison. "Brown had just been put out on his arse by the public. It wasn't a question of what we thought. It was a question of what the nation had said about him in the election," he said.
Miliband and Cameron must also be prepared for an "older, wiser and uglier" Lib Dem coalition negotiating team than was deployed five years ago.
"I think that most Lib Dems feel that the coalition government has been a success, but that we have been quite bruised by it. We feel we have spent five years being shafted by the Tories and I think our attitude sitting down at the outset of any further coalition with either party would be to say: 'now look here, we've just spent five years being shafted by the Tories, if you think we are going to spend five years - I suppose I am thinking here about talking to Labour - being shafted by you, you've got another thing coming'."
There is also the question of whether it would actually be worse for the Lib Dems to do a deal with Labour. Harvey suggested it would be harder for the Lib Dems to differentiate themselves from a party that was politically more aligned. In the present coalition the Lib Dems like to be the heart to the Tory's head. In a Lib-Lab deal, the yellow team could end up playing the role of the bad guys.
"I think it is true that nobody really thinks we are proxy-Tories," Harvey argued. "People spinning out Labour rhetoric might wish to try and paint us as that but I don't think the country believes it. I don't think even those pushing the rhetoric really believe it either.
"I think if we were in with Labour we would look a bit more, in some eyes, like the rural arm of the Labour Party. The rural and suburban wing of the Labour Party. I think it would be much more difficult. Because we are both parties of the centre-left."
In an interview with The Huffington Post in November 2013, Harvey predicted that Labour would win the election with a majority, unless there was a "game changing event". That event happened. And it happened in Scotland.
"I think the game changing event, bizarrely, has proved to be Scotland," he said. "At the time, Scotland was on my shortlist of game changing events, but not, I have to say, in the way it has panned out. The game changing event would have been if the Scots had voted for independence. I had no more imagined this than anyone else had. That they would vote to stay in but Labour would collapse in the process it is the most bizarre outcome of that saga."
Just than 24-hours after Harvey expressed his surprise at the Nicola Sturgeon's SNP surge, constituency polling published by Lord Ashcroft suggested that Labour, and the Lib Dems, will be annihilated in Scotland.
"They [the SNP] are now an element in the equation in a way that nobody could have anticipated and which is almost exclusively at Labour's expense," Harvey observed. "It is now much tougher for Labour to win, but not impossible. It is pretty unlikely they are going to win outright on their own. As the polls stand at the moment they are are still on course to be the largest party."
However Harvey marvelled at why none of his colleagues in parliament shared his view. "Nobody in the Westminster beltway appears to believe that is going to happen. Absolutely everybody seems to think the Tories will come out as the largest party. Which might be true, but something is going to have to happen to cause that, that is not the trajectory."
"I think the Tory and Labour Party votes will each be around 32% or 33%. The number of seats will be around about the 280 or 285.
"Then the question is do we have enough to get them to 326 [a majority]. The more SNP MPs there are the less likely we will.
"It's not the view in the beltway. The view in the beltway is the Tories will get through the 300 barrier and Labour won't come back with many more seats than they have got now. For that to be true something has got to shift. And I have been hearing form the Tories for four and half years now that it will all swing their way at the end. I'm still hearing that from the Tories.
"It was all meant to happen when the economy started improving. Well the economy started improving in June 2013. We are now in February 2015."
Harvey added: "They are leaving it devilishly late."