Tony Blair and Gordon Brown will attempt tomorrow to recreate their joint campaign of the 2005 general election by campaigning together in Scotland.

The Prime Minister and Chancellor, it emerged yesterday, will use a visit to Scotland to begin what sources said would be a “big economic attack” on the Scottish National Party and the cost of independence to Scottish households.

The decision by Labour’s two heavyweights to mount what could be one of their last joint electioneering efforts before Mr Blair leaves office is a measure of the deep concern inside the Labour campaign at what appears to be unstoppable Nationalist momentum in the run-up to the elections north of the Border next month.

Yet another opinion poll yesterday — the fourth in five days — put the Scottish National Party well ahead of Labour in both first-past-the-post and PR sections of the Scottish Parliament election, confirming a trend first indicated by a Populus poll in The Times last week.

The implications of such poll findings being repeated at the election on May 3 are serious for Mr Blair and Mr Brown. Mr Blair will not want to be remembered as the Prime Minister whose introduction of devolution paved the way for the break-up of Britain, and Mr Brown will not want to be entering 10 Downing Street only a few weeks after the Nationalists have won power in his own political backyard.

The decision by the two to face the SNP threat together comes at a time when Labour strategists are bemused at the party’s failure to get Scots to believe that independence will follow inevitably from the election of a Nationalist Scottish Executive in Edinburgh. The polls are also in agreement that there is no surge of support for independence with only one in four Scots backing separation. “We aren’t managing to pin the independence tail on the SNP donkey,” said one Labour source.

The Prime Minister and Chancellor can be expected to drive home Labour assertions that every household in Scotland will face a £5,000 bill if they elect the SNP, and that independence will mean an £11 billion “black hole” in the Scottish economy.

However, some senior Labour figures in Scotland believe that Mr Blair’s intervention may not be all that helpful. While they accept that the Prime Minister is a formidable political campaigner, they believe that each time he comes to Scotland he reminds undecided voters of the Iraq war debacle and the row over cash for peerages.

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