Mr Duncan Smith promised better services

During the trip he met party leaders in Edinburgh and took the campaign trail to the East Renfrewshire constituency of Eastwood.

Meanwhile, the Liberal Democrats were pitching for second votes while campaigning in Aberdeen.

And the Scottish National Party was concentrating on the economy with the launch of a new website.

Improving services

Mr Duncan Smith said the Conservative campaign was going well north of the border.

He said people were responding to the Tory message on cutting government "waste".

He claimed the Conservatives were the only party who would tackle inefficiencies and spend the savings on improving services.

"Under Labour and their friends we have more tax, more waste and more failure," he said.

The debate on the future of the economy is central to this election campaign Andrew Wilson SNP economy spokesman

"It's only a Conservative Party having responsibility that will actually be able to cut the waste and produce for people better services and reasonable levels of tax.

"That is critical because people can't pay more and more in tax and have less to show for it."

He also accused Labour of lying over claims that the Tories wanted to slash public spending in Scotland by �4bn.

Mr Duncan Smith said Labour, the Lib Dems and the SNP were in a "contest" to see who could spend the most.

Meanwhile, the SNP launched its Succeed in Scotland strategy, aimed at bringing more company headquarters north of the border.

'Crucial debate'

It includes plans to persuade UK firms to locate their headquarters in Scotland or convert branch operations.

The SNP also launched a website - soyouthinkyoucanrunscotland.com - featuring a game which allows voters to play first minister.

Economy spokesman Andrew Wilson said: "The debate on the future of the economy is central to this election campaign and this website is designed to engage as many voters as possible in this crucial debate.

The SNP launched an internet game

"It takes our boardroom campaign to the internet generation using the very latest multimedia approach."

The Scottish Liberal Democrats launched a drive for more regional list votes.

Party president Malcolm Bruce targeted the 750,000 people whom he said chose Labour with their second vote in 1999 but failed to elect any additional MSPs.

"In this election they have a clear choice," he said.

"Vote Labour and achieve nothing. Or vote Liberal Democrat for radical improvements in public services with more nurses, doctors, teachers and police officers.

"Vote Liberal Democrat to improve our environment and build a better skilled workforce with more jobs."