A BBC poll has reportedly found that most voters in England believe Scottish MPs should be barred from becoming Prime Minister but only one in five agree north of the border, it emerged yesterday.
Scottish Nationalists claimed that the findings of the ICM survey, conducted for BBC1's The Politics Show, were "bad news" for both Tony Blair and his widely-tipped successor and Fife-based MP Gordon Brown.
Across the UK, 52 per cent of respondents said it was wrong for an MP north of the border to become PM now that Scotland has its own Parliament.
The figure was 55 per cent for England and 59 per cent in the South-east but just 20 per cent in Scotland, according to the Sunday Mail newspaper.
SNP leader Alex Salmond: "This poll is bad news for Labour.
"It means the current Prime Minister is deeply unpopular in Scotland while the future Prime Minister is unacceptable in England.
"It shows Gordon Brown's new-found Britishness cuts no ice either north or south of the border."
But a Labour spokesman insisted: "The people of Britain will pick the next Prime Minister based on his ability to deliver a strong and stable economy and a secure future."
The poll findings follow claims by former Labour minister Frank Field that new Home Secretary John Reid, also a Scottish MP, will challenge the Chancellor for the keys to Number 10 when Mr Blair steps down.
Scottish First Minister Jack McConnell said that Tony Blair had proved himself an electoral asset, but Gordon Brown would also make be an "outstanding" Prime Minister.
"He has been an outstanding Chancellor and I have no doubt that he would be one of the great holders of that office if he succeeds Tony Blair," he said.
Labour's heir apparent Gordon Brown still needs to convince voters he could be a political "winner", says former Labour minister Frank Field.
He said the Chancellor must use the transition period at the end of Tony Blair's premiership to convince people of his abilities.
"The next few years . . . do give Gordon Brown a glorious opportunity to show that he has a style of operating which both the parliamentary party feels at ease with and also looks as though we can win elections," he said.
"The great legacy of this Prime Minister is that he has won elections like no other Labour Prime Minister ever. Therefore if he loses that ability as we face the next election I think we really want two things.
"We want a Government which is more relaxed, less centralised, less freak-controlled than is this Government, and we also want a leader who is happy with himself and the party so that the electorate see that person as a winner. I would suggest Gordon Brown spends the next two years achieving that objective."