Michael Howard has apologised for the "mistake" of introducing the poll tax.

Speaking during a visit to Scotland, the Conservative leader said the policy had been a "brave experiment but it didn't work".

Both Labour and the SNP have sought to brand Howard as "Mr Poll Tax" but the Tory leader sought to draw a line under the criticisms during his tour of the UK.

"Obviously the poll tax was a mistake and I have apologised for it," he said.

"It's ironic because it was brought in principally to deal with a problem of rating revaluation in Scotland.

"But clearly it didn't work. It was a bold and brave experiment but it didn't work, it was a mistake, I've apologised for it before and I'm happy to do so again."

Alex Salmond, the SNP's Westminster leader, had earlier demanded the apology but added that Howard "has a lot more to be sorry for".

"I am glad that Michael Howard has responded to the SNP's challenge, and apologised for the poll tax. That is certainly progress," he said.

"But as a minister in the Tory governments of the 1980s and 1990s, Mr Howard has a lot more to be sorry for."

He added that "perhaps Michael Howard could also apologise for the Tories' disastrous record on fishing, unemployment and the NHS".

"We need to know whether Mr Howard has undergone a real conversion - or whether he is just penitent under pressure," he said.