Scotland's First Minister, Alex Salmond, today challenged Gordon Brown to a head-to-head debate in the run-up to the crucial Glenrothes by-election.

The SNP leader warned that he is ending the political truce agreed during the current banking turmoil - after Mr Brown claimed Scotland could not have tackled the banking crisis on its own.

Mr Salmond said the nationalists are on course to pull off a shock in the vacant seat next month, similar to the "political earthquake" they caused after overturning a Labour majority of 10,500 to win Glasgow East in the summer.

"I detect that the political earth is still shaking from Glasgow East and it's going to be felt next here in Glenrothes," he said.

The SNP leader was joined by the party's candidate for the seat, local council leader Peter Grant, at Scottish Second Division side East Fife's Bayview ground today in Methil to launch the nationalists' campaign.

Mr Salmond said rising energy costs will be among the key issues in the campaign and predicted action in these areas as "the political pressure mounts".

He also reiterated his weekend calls for a £1 billion package from Westminster to help reflate the Scottish economy, including £120 million held by energy watchdog Ofgem for Scotland.

Mr Salmond welcomed Mr Brown's plans to campaign in the constituency.

"Battle will be joined and the issue will be toe-to-toe," Mr Salmond said.

"I'll be delighted to meet Gordon on the campaign trail - who knows, we might meet up on it somewhere.

"I would be delighted, incidentally, to debate with the Prime Minister."

He added: "I will be delighted to debate with the Prime Minister anywhere in this seat.

"I'll do it in the park in East Fife at New Bayview here. I'm very happy to do that."

Mr Brown said last night that a Scottish administration could not have masterminded a similar bail-out of the banking system to the £37 billion package he announced this week.

The First Minister said he had told Chancellor Alistair Darling that he would "suspend" normal political crossfire during the crisis.

Mr Salmond said: "Obviously he (Mr Brown) feels, and let's all hope, that the emergency situation has calmed down.

"I can only interpret the decision to resume political hostilities in that light, therefore he will now be subject to the same examination politically that normal times demand."

He added: "In particular we can examine who the author of the 'Age of Irresponsibility' actually was."

Mr Salmond also said the SNP would not shy away from the issue of independence after question marks were raised about the toll of the economic turmoil on countries like Ireland and Iceland - previously held up by the nationalists as examples for Scotland to follow.

"Our policy of Scottish independence underlines everything we do," he said.