This year's General Election has been tipped as the closest in living memory. The University of York's Professor Neil Carter, an elections expert, gives his view of the fight ahead.

THIS is the most unpredictable election I can remember, and probably one of the closest.

It is unpredictable because of the weakness of the three major parties and the buoyancy of several ‘minor’ parties.

In the past, minor parties have flattered to deceive, doing well in mid-term by-elections but then disappearing as election day approaches. But UKIP’s vote is holding up, the SNP is buoyant, and there is much talk of a ‘Green surge’.

Will UKIP take mostly Conservative or Labour voters? Which seats will they do best in? Will a strong Green performance stop Labour winning many of its target seats? Just how badly will Labour implode in Scotland? Where will all those Liberal Democrat voters go?

Throw away the swingometer, this election is truly up for grabs.

Locally, the really interesting contest will be in York Central. Hugh Bayley leaves a respectable but potentially vulnerable majority of 6,451. Labour will no longer benefit from his incumbency - Bayley was widely regarded as a hard-working MP who stood up for constituency interests.

It is hard to see the Liberal Democrats getting anywhere near the 11,694 votes they got last time to put them third, so where will those votes go and those of many other people disillusioned with the established parties?

Normally we’d expect them to vote Labour or Conservative, but maybe not this time. UKIP will certainly pursue the protest vote: they polled strongly in last year’s European Parliament election and will hope to build on that support. The Greens have two councillors and growing strength at local level, particularly amongst students; indeed, rather optimistically they have made York Central one of their 12 target seats.

Although Julian Sturdy secured a smaller majority of 3,688 for the Conservatives in York Outer in 2010, the collapse of the Liberal Democrat vote nationally suggests that he might have a much easier ride this time. But, then again, nothing is certain in this election.