Loser: Gordon Brown's popularity has plummeted further despite Labour's three-point comeback

Gordon Brown's personal popularity plumbed new depths today as it emerged that he will not campaign in the crunch by-election in Glasgow East.

A Populus/Times poll found that three quarters of voters now viewed the Prime Minister as a "loser", while 67 per cent saw him as a weak leader.

The survey put the Conservatives on 41 per cent, Labour on 26 per cent and the Liberal Democrats on 19 per cent.

On the economy, the Tories have moved into a 13-point lead as the best party nation's finances.

Mr Brown's supporters can draw a crumb of comfort the fact that although his own ratings are still dire, Labour's sharp fall in popularity appears to have bottomed out.

The party is up three points on a month ago, while the Tories are down four.

The poll came as Scottish Office Minister David Cairns confirmed for the first time that Mr Brown would be staying away from Glasgow East ahead of polling day on 24 July.

David Cameron was in Glasgow yesterday and all other party leaders will hit the campaign trail as the SNP tries to overturn the massive 13,500 majority in the normally safe Labour seat.

At the height of Labour's popularity in 1999, Tony Blair campaigned in the Eddisbury by-election, declaring that it was important to "lead from the front".

But Mr Cairns said that was unusual.

"Only once in 30 years a prime minister has gone to fight in a by-election," he said.

Labour tried to get on the front foot today with the first day of campaigning by its newly selected candidate Margaret Curran.

Ms Curran was chosen to fight the seat last night after a weekend of chaos saw the withdrawal of the party's first-choice contender.

Ms Curran faced accusations of hypocrisy as she is also an MSP in the Scottish parliament and has previously attacked SNP leader Alex Salmond for retaining his Westminster seat after being elected to Holyrood last year.

Mr Cairns said that electing Ms Curran would save money. "She would be representing exactly the same people and would draw one salary," he told the BBC.

Mr Salmond predicted that if Labour lost, it would change fuel and energy policies in a bid to save Mr Brown's job.