Conservative voters are rallying to the aid of Scottish Labour leader Jim Murphy in a bid to stop the SNP winning his seat, according to a new poll.

A previous local survey of East Renfrewshire, where Mr Murphy is struggling to be re-elected, showed the Westminster MP nine points behind his SNP challenger and set to be booted out of parliament.

But a new poll released by Lord Ashcroft this afternoon showed Mr Murphy narrowing the gap to three points, largely due to a sharp increase in Conservative voters saying they would vote Labour.

Nearly a quarter of those who voted Conservative in the area in 2010 now say they plan to vote for Jim Murphy as the battle enters its final phase.

Labour’s share in the seat was up five points, while the Tories’ was down five, according to the poll.

Jim Murphy, right, in front of a Labour poster from the 2010 election campaign (GETTY IMAGES)

If repeated on election day the result would still see the SNP win the seat, however.

“[The gap narrowing] seems largely down to Conservative voters – the Tory share is down five points, and Labour’s up five, since my last survey, and remaining Conservatives are less likely to rule out moving to Labour than in most seats,” Lord Ashcroft, who commissioned the poll wrote in an analysis.

The unionist united front comes a week after former Tory chairman Lord Tebbit told the party’s supporters in Scotland that they should vote Labour to stop the SNP from winning.

“From the Tories’ point of view we are not going to come home with a vast number of seats from Scotland. We know that. So the choice is would we rather have a Scot Nat or Labour? I think, on balance, probably a Labour MP would be a more reasonable thing to have,” he told the Guardian newspaper.

A series of polls from different firms have shown the SNP set to take over half the vote in Scotland in an unprecedented landslide.

Some projections suggest the SNP could take every seat in Scotland, though some local battles will be tough to crack in practice.