The SNP has stepped up its attack on Labour over health policy north of the border.

Nationalist leader Alex Salmond said Labour had been "caught red handed" making claims in Scotland that only apply to England.

And deputy leader Nicola Sturgeon was on Monday set to hand in a letter to Labour headquarters in London calling on Tony Blair to retract one of the party's claims.

The row comes after a letter from John Prescott, apparently distributed in Scotland, said that Scottish Labour pledges on the NHS were "similar" to those in England.

However, the letter's reference to a maximum waiting time of 18 weeks for hospital treatment is only applicable in England, with a 36 week wait the comparable policy in Scotland.

"Yesterday, the Tory leader was made to apologise for making misleading claims in a letter about health," Sturgeon's letter said.

"Tony Blair accused the Tories of running a 'nasty and unscrupulous' campaign after they admitted producing misleading health figures.

"The prime minister, as leader of the Labour Party, must now apologise for allowing his party to deliberately mislead Scottish voters."

Meanwhile, Salmond was set to hit the campaign trail in the Na h-Eileanan an Iar constituency, accusing Labour of "trying to hide from their lousy Scottish record".

"On the economy and health Labour has been caught red handed focusing on English success and pretending it applies to Scotland," he said.

"They can talk up success south of the border, but can't hide their failure in Scotland."