Both Labour and the SNP aree desperately mobilising their supporters in the Glenrothes constituency this evening as both parties reported that the outcome of the crucial by-election is too close to call.

By early evening, turnout in the constituency was estimated at around 35 per cent but likely to go above the 50 per cent mark by the close of the poll.

The result is crucial to Gordon Brown, the Prime Minister, who wants to show that he can translate the recent world-wide praise for his handling of the global financial crisis into votes on the domestic front.

The SNP believe they can chalk up another victory by overturning the 10,664 Labour majority gained in the seat in 2005, to add to their specectacular triumph in Glasgow East in July where they achieved a swing of 22 per cent to oust Labour.

Voting was reported to be “brisk” by mid-afternoon and campaign managers in both main parties were optimisitic that it would top the 56 per cent achieved at the 2005 general election.

Although Labour have been in possession of the seat at Westminster, the corresponding constituency of Fife Central at Holyrood is held by the SNP.

Glenrothes is the neighbouring constituency to Mr Brown’s own seat of Kirkcaldy and Cowdenbeath and he has broken with Prime Ministerial convention by campaigning twice in the by-election. His wife Sarah has also been on the campaign trail around half a dozen times.

The result is also vital for the SNP, who want to show that Glasgow East was not a one-off and that there are now no safe Labour seats north of the border.

Both Lindsay Roy, the Labour candidate, and Peter Grant, the SNP candidate, voiced optimism about the outcome yesterday as they cast their own votes in the by-election.

The poll also dominated First Minister’s Questions at Holyrood yesterday with Alex Salmond, the First Minister and SNP leader and Iain Gray, the Labour leader in the Scottish Parliament, trading verbal blows at First Minister’s Questions.

The exchange took on a personal edge when Mr Gray told MSPs: “I have to say the First Minister is no Barack Obama.”

This drew the retort from Mr Salmond: “It‘s certainly true I‘m no Barack Obama. The problem for Iain Gray is, he is no Jack McConnell.”( a reference to Mr Gray’s predecessor as Scottish Labour leader).

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