Jack McConnell found time for a second successive day on the campaign trail with the Chancellor yesterday, but again sidestepped a head-on debate with SNP leader Alex Salmond.

A BBC radio debate in Eyemouth last night had Work and Pensions Minister Jim Murphy filling the Labour chair, facing down the SNP.

The previous night, a televised Question Time debate in Edinburgh had Lord Foulkes employed in the Nat-bashing role, during which he reignited the controversy started by Liberal Democrats at the weekend by again referring to the SNP as xenophobic.

Lord Foulkes, former Ayrshire MP and now standing for Holyrood on the Lothian list, said Mr Salmond's references to "London Labour" were xenophobic, prompting the SNP leader to say it was "legitimate and honourable" for people to seek self-determination.

The SNP yesterday renewed calls for Mr McConnell to go head-to-head with Mr Salmond, publishing a mock "missing" poster featuring the First Minister.

SNP campaign director Angus Robertson claimed the Labour leader's refusal to appear on the show was the seventh time he has declined to debate with Mr Salmond. He also claimed that Mr McConnell has now rejected 15 invitations to appear on the programme.

Mr Robertson added: "Previous First Ministers of Wales, Scotland and Northern Ireland have all debated on this prestigious programme, so what exactly is he so scared of? If Labour were confident of their arguments they would debate them in public, and if Mr McConnell believed in what he was saying, he would go head to head with Alex Salmond like his predecessors."

YouGov polling, commissioned by the SNP, shows a big majority of voters want to see the main contenders to be next First Minister debate with each other, by 70% to 14%, with the remainder undecided.

The majority is even greater among those identifying themselves as readers of The Herald, with 75% in favour compared with 18% against. The issue was first raised by the SNP last month when the First Minister turned down a long-standing invitation from Edinburgh Chamber of Commerce for a big set-piece debate at the city's conference centre.

But Mr McConnell's camp insist that for now he is concentrating on running the country and he will only debate with other party leaders when the election campaign begins at the end of the parliamentary session.

"Alex Salmond could have debated with Jack McConnell every week of the year if he hadn't deserted the Scottish Parliament for the bright lights of London," said an aide.

"Question Time only approached the First Minister two weeks before the event and this week he has already been involved in Ask Jack' sessions with large audiences in Edinburgh and Kilmarnock and he will be doing the same in Glasgow next week."

But the fact that Mr McConnell could find time to hit the campaign trail two days running with Mr Brown in Edinburgh and Fife, and make himself available for radio programmes such as Ask Jack' on an unopposed basis was held up by the SNP as clear evidence that he was running scared.

Annabel Goldie, the Scottish Conservative Leader, said: "I can understand Jack McConnell being wary of defending his record in public, but the fact is it doesn't matter who the Labour messenger is. Their message is bad, their record is worse.

"This election is about more than just personalities. Alex Salmond naturally wants to make the contest into a big man face-off' between him and the First Minister, in order to disguise the fact his party has only opposed eight LibLab pact bills in eight years.

"The LibDems will naturally hope no-one notices they are in government. And the First Minister will naturally try to hide from debating with anyone, for fear of being found out."