The YouGov poll, commissioned by The Sunday Times, finds that 44% of Scots want independence, compared with 42% who favour continued rule from Westminster.

The poll shows support for independence has almost doubled since 2000, a year after the founding of the Scottish parliament. Devolution at that point seemed to have damped down nationalist feeling, with ICM finding only 23% of Scots favouring full independence.

Alex Salmond, the Scottish National party leader, has said he intends to hold a referendum on independence if he wins power. Next year is the 300th anniversary of the Act of Union.

Tony Blair’s difficulties and voters’ discontent with policies such as the Iraq war are believed to have contributed to a drop in support for Labour in Scotland and fed through into increased backing for independence.

Some Labour MSPs want the prime minister to resign quickly because they believe his unpopularity is putting the future of the Union at risk. “A lot of us are worried, especially with what’s been going on in London, that the whole thing is going to blow apart if we become disunited and forget the bigger picture,” said one.

Last Friday Gordon Brown, the chancellor, who will mastermind Labour’s campaign for next May’s Scottish elections, spoke out against nationalist sentiment with a warning that independence would be economically disastrous and force millions of Scots to classify relatives in England as foreigners.

The YouGov findings also reflect a disenchantment among voters at the limitations of devolved government. While the parliament at Holyrood has the power to legislate in areas such as health, education and transport, it has limited financial powers and is dependent on a block transfer from the Treasury for most of its budget.

In Scottish elections, the electorate are allowed to vote twice, first for a group of MSPs elected in a Westminster-style first-past-the-post system and second for a group elected by proportional representation.

The poll of 1,200 Scots voters, conducted at the height of the prime minister’s difficulties between Tuesday and Thursday last week, showed the SNP at 29% for the first ballot, just one point behind Labour.

The Nationalists were ahead of Labour on the second ballot by 29% to 27%.

Scottish voters have proved immune to the “Cameron effect”, however, despite the Tory revival in England. The Conservatives are backed by just 14% of voters, below the Liberal Democrats.

If repeated at a Holyrood election, the result would give the nationalists 38 out of 129 seats, enough to form a coalition with the Liberal Democrats, Labour’s current governing partners, and the Greens. Labour would remain the biggest party with 42 seats, down from 50.

Explore UK News

• Crime News

• Education News

• Health News

• Science News

• Scotland News

Times Recommends

• Olympic-size television coming to your town
• Mosley opens new front in battle for privacy
• Decorator fined for smoking in van