The Liberal Democrat leader said any administration would have to be able to govern - and restated his staunch opposition to any combination that relied on the support of the SNP or Ukip.
With opinion polls indicating that a combination of the Lib Dems with either Labour or the Tories would not deliver a working majority, Mr Clegg’s stance indicates his willingness to take his party into opposition rather than risk the potential chaos of a minority administration.
The Lib Dem leader has said the country could face a second general election before Christmas without a stable coalition government involving his party.
He told the Press Association a coalition was “very likely” after May 7 and “compared to the other alternatives - certainly with the Liberal Democrats in it - I think it is a more desirable outcome than the factionalism, instability and divisiveness of minority government on either the right or the left”.
But pressed on whether he would form an alliance with either the Tories or Labour that failed to deliver the required majority he said: “A government has to govern, so you also have to have the means to govern.
“I have certainly made it quite clear that I am not going to enter into any pacts, deals or arrangements which would in practice mean that a government is on a life support system which can be switched off by Nigel Farage or Alex Salmond, so there you have your answer.”
Asked if a minority coalition arrangement was off the table, he said: “I’m just saying that we have provided strong and solid leadership in this coalition government, in part because we had a strong majority.
“I’m not going to start dramatically ruling out other permutations, but I have to say I think the most desirable one is clearly a coalition government which can govern and get its business through the House of Commons, that’s stating the bleeding obvious.
“But what is becoming increasingly obvious to me is that the best way to ensure that happens is to have more Liberal Democrats in the House of Commons. The bigger we are, the more likely we can carry the numbers.”
Mr Clegg continued: “I’m expressing a very strong preference for a government that can govern, and governments can govern most effectively when they have a working majority in the House of Commons.” The Lib Dem leader acknowledged that coalition negotiations would take longer than in 2010, but insisted that “we don’t have to end up like Belgium” where lengthy periods elapse without a government.
Asked how long it would take for his party to approve a deal, he said: “It could be done relatively quickly, it doesn’t need to take weeks and months, far from it. We don’t have to end up like Belgium, which sometimes appears to have more years where it doesn’t have a government than it has years with a government.
“But nor do I think we should be unreasonably impatient. It’s better to get it right than rush and get it wrong.”
Mr Clegg said he would try to “read the tea leaves” as soon as possible on Friday to assess the likely nature of the next government.
But he predicted that any negotiations would be drawn out, partly because of the “wariness” in his own party at the prospect of another coalition, but also by the responses of Labour and the Tories to failing to secure an outright win.
He said: “I am going to try to read the tea leaves as quickly, and with as clear a head as I possibly can, to understand what are the instructions that have been given to us by voters and, obviously very quickly I will want to consult with colleagues and get a feel for what sentiment is like and then we will take it step by step.
“Frankly, a lot of what the Liberal Democrats do is in part determined by how grown up and reasonable other parties are. At the moment they appear to be acting less reasonably, in a more immature fashion, with each passing day of this campaign.”
In 2010, Mr Clegg said he came under intense pressure to move quickly to form a government in order to calm the markets.
“I was being telephoned by pillars of the British establishment on an hourly basis saying ‘please, please get your skates on, we desperately need a government before the bond markets open tomorrow morning’,” he recalled.
Now, while there were “serious market jitters” and “we can’t take market tranquillity for granted”, the situation was not as desperate.
With the state opening of parliament scheduled for May 27, he said: “You should definitely know within that period of time whether there is a deal to be done or not, definitely, if not sooner.
“But we had this breathless demand within about 24 hours last time that a government must be formed by teatime. I just think we have to accept that it might take a bit longer. In fact it will take a bit longer.”
It would be “irrational” for the Lib Dems not to be wary of another term in office after the electoral defeats inflicted on them since 2010.
But Mr Clegg added: “I think there will be more protracted debate in all the parties. If you look at the way in which right wing of the Tory party appear to be manoeuvring already to ensure that David Cameron can’t enter into a centre-ground coalition because they want to create this Blukip alliance on the right.
“For them, if the Conservative Party don’t get a majority, as they won’t, their instant analysis will be that the Conservative Party wasn’t right wing enough.
“So far from pulling the party back to the centre, they will be wanting to pull it further to the right.
“In Labour you have got exactly the same dynamic going in a left wing direction, people in the Labour Party saying, far from trying to reach an accommodation with us in the centre, the Labour Party should try and outflank the SNP on the left.
“Both those lurches, to right and left, would be a disaster for the country and I’m not going to budge from the centre ground.”
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