Labour claimed yesterday that the party had turned the tide in the Glasgow East by-election, with former SNP voters returning to the fold.

The latest opinion poll today is expected to show Labour leading their challengers by 17%, a similar margin to a poll last weekend, indicating that the party was preventing any further inroads into its 13,500 majority.

Labour candidate Margaret Curran claimed: "I have met a number of people who voted SNP in the past who are now switching to Labour, and I am confident about that.

"I never have and never will take any vote for granted. I will fight right up to 10pm on Thursday night, but I do believe the message I'm taking to the doorsteps is resonating with people.

"I think they do believe they need someone whose first priority will be the east end of Glasgow, who believes they have a job to do at Westminster, and who will talk about their issues rather than constantly talk about independence."

The SNP are continuing to make a huge effort in the constituency where their party campaigners believe the numbers who are undecided put the outcome on a knife-edge.

Nationalist candidate John Mason campaigned yesterday on post office closures and high energy prices. Responding to a report that gas prices could rise by as much of 70%, he called on Chancellor Alistair Darling to implement an eight-point plan to tackle fuel poverty.

He said measures should include a mandatory "social tariff" to be introduced by all energy companies and action to ensure that those paying for gas or electricity by pre-payment meters are not penalised.

"That has been the number one issue on the doorsteps - rising prices of petrol, gas and electricity," he said. "If we have another Labour MP, Gordon Brown is going to take that as a message that what he has been doing at the moment he can just carry on as before."

The battle for third place in the by-election continued with Tory candidate Davena Ranking campaigning with MEP Struan Stevenson to complain that at a time of high food prices Britain's poor were missing out on an EU food distribution programme worth £240m.

"Britain was a member of this scheme for 11 years before Labour came to power, but in 1998 Tony Blair pulled the UK out, stating that such policies should only be addressed at national level," said Mr Stevenson.

The Liberal Democrats stepped up their campaign to save Parkhead fire station which is threatened with replacement by a merged larger station further away in Cambuslang.

Candidate Ian Robertson criticised Labour and the SNP for failing to join the campaign. "Labour and the SNP are too busy playing play school politics and have lost sight of the real issues affecting local residents," he said.

But the Fire Brigades Union said it had been the last Labour-LibDem coalition at Holyrood which voted for changes which had allowed the firemaster to propose the merger.