Labour braced for dual Celtic challenge

A last-ditch appeal for a cross-party alliance of Labour, Tory and Liberal Democrat voters has been made by Jack McConnell, Labour's first minister in Scotland, in a bid to stop the SNP winning control of the Scottish Parliament.

Mr McConnell said Tory and Liberal Democrat voters should back Labour as the "only way" to stop Alex Salmond, the SNP leader, taking power after a YouGov poll put the SNP on 38 per cent, eight points ahead of Labour, and on course to become the biggest party at Holyrood. But Liberal Democrat leaders in London dismissed the suggestion of a voters' pact, saying: "It's just not realistic."

Sensing a historic victory that could put the Union back on the agenda, Mr Salmond tried to ease some voters' fears by saying independence was "not a one- way street". He said: "It can vote to become independent and it can vote, if it so chooses, to become un-independent; that's the prerogative of a national assembly ... it's not a one-way street."

Labour leaders Gordon Brown and Tony Blair will step up their warnings about the economic blow to Scotland that independence would bring.

They privately say they have just three days to avert the political earthquake of a Scottish nationalist victory in the poll.

The prospect of an SNP victory this week at the polls, and a government committed to Scottish independence at Holyrood, would produce a disastrous backdrop for Mr Brown as he prepares to take the reins of power. Labour has launched a string of increasingly strident attacks on the nationalists, emphasising the cost of independence and how much taxes would go up.

On Friday Mr McConnell, the Scottish Labour leader, will rally his demoralised troops, insisting there was "all to play for".

Labour strategists believe the SNP support will soften as polling day approaches. He insisted that the election "is not a game", amid Labour fears that they are falling victim to the unpopularity of the Westminster government and uncertainty in the final days of Mr Blair's premiership.

Tavish Scott, a Liberal Democrat minister in the ruling Lib-Lab coalition, said the party would target opposition to independence in the final days of the campaign to persuade voters away from the SNP. He said: "The logical place for people to turn is the Liberal Democrats.

"Inevitably, the polls are going to tighten and there have to be large caveats in a system of PR compared with a first-past-the-post system."

David Cameron, meanwhile, will visit Glasgow today to bolster the poll hopes of the Conservatives, currently the fourth party in the Scottish Parliament.

A poll of polls, conducted for The Independent last week by Professor John Curtice of Strathclyde University, showed the SNP's support was solid at fivepoints clear of Labour.

However, Scotland's political parties enter the final push for votes this week knowing that the real job of deciding who governs north of the border will only start once the voting is finished.

The complex Scottish electoral system which combines one-member constituencies with a regional top-up of seats based on proportional representation, makes it virtually impossible for one party to secure an overall majority.

That would leave the SNP seeking coalition partners or attempting to govern as a minority administration .