Deputy prime minister Nick Clegg
Nick Clegg has prompted speculation over his future

It is one of the political questions to which there is probably no right answer – how long do you intend to remain as leader?

But Liberal Democrat leader Nick Clegg walked straight into it and managed to give two contradictory answers that not only overshadowed his end-of-conference speech at the weekend but also declared open season on his future.

Needless to say, the deputy prime minister did not actually say anything. In the tradition of such things, he left it to his aides to "send out his message".

As his party's otherwise successful Spring conference drew to a close speculation over the leadership rattled around the media as treasury secretary Danny Alexander appeared to be emerging as the strongest contender for the succession.

Clegg's office issued a statement saying: "It's up to the British people to decide but if Liberal Democrats are in government again after 2015 he would like to serve a full term." That was immediately read to mean, if there was no coalition he would quit.

Panic ensued so a second statement was issued declaring: "Nick Clegg intends to be the leader of the Liberal Democrats today, tomorrow, into the 2015 election and through the whole of the next parliament. He intends to be leader of the Liberal Democrats whether or not we're in government."

That is marginally worse than the first answer because at least that one was realistic.

The second simply begs the response that it will not be up to Clegg to decide whether he stays. First, it will be up to voters and whether or not they decimate the party at the general election.

Then the party membership will have their say and, finally his own frontbenchers' views and manoeuvrings will be crucial to his prospects.

This matters because, until now, any speculation over Clegg's future has been just that. Now he has given his party and the media the green light to press him further and encourage would-be successors to sharpen their daggers.

And it has the potential to become a running sore and a distraction from the main business of maximising his vote at the general election.

And the truth is, it will not be in his hands. There is a growing sense in Westminster that neither Labour or the Tories relish the idea of a coalition and might prefer to try ruling as a minority government.

And, in any case, Labour's natural antipathy towards the Lib Dems might make a coalition with Clegg impossible anyway. Danny Alexander might also suffer because of the way he has appeared to be "embedded" in the Tory part of the coalition. Another leader such as Vince Cable may be more appealing.

Recent precedents show just how undermining such statements can be. During the 1983 election campaign a senior union leader made a statement declaring: "Michael Foot is Leader of the Labour Party", no one had doubted it until then but they certainly did afterwards.

After the 1987 general election, Margaret Thatcher gave a TV interview in which she said she wanted to go "on and on" as prime minister, which led to some outrage that she was over-reaching herself.

Then in 2006 prime minister Tony Blair, under huge pressure from rival Gordon Brown, announced he would stand down within a year and hoped that would end the in-fighting. It only led to demands for a specific date from him.

So, trivial though such statements may appear, they can have a hugely destructive and distracting effect on leaders and their parties. Not what the Lib Dems need just at the moment.