Scotland's First Minister Alex Salmond today defended his claim that sterling was "sinking like a stone".

Political opponents said his comments - made on Spanish television - could harm the economy.

Mr Salmond outlined his view during a series of television interviews on a trip to Barcelona before Christmas.

It was reported that Mr Salmond was asked about a recent rise in support for Prime Minister Gordon Brown.

Mr Salmond told his Catalan interviewer that the case for growing the economy in Europe - with economic decisions made in Scotland - was becoming a strong one with voters.

"As you know, we're in sterling and sterling is sinking like a stone. It's now about parity with the euro," he said.

The First Minister's spokesman said today the SNP has always recognised the benefits of euro membership, subject to the consent of the people in a referendum.

"And there is no doubt that the plummeting pound and parlous state of the UK economy has caused many people in the business community and elsewhere to view membership favourably," the spokesman said.

Tory MP David Mundell, the shadow Scotland secretary, said economic problems were caused by the Labour Government at Westminster, not a flaw with sterling.

"If Scotland did abandon sterling because it was sinking like a stone and took on the euro instead, Scottish goods and services would risk being priced out of the rest of the UK," Mr Mundell said.

"The SNP has to explain where the logic is in believing that Scottish interests are lost in a union with a common language, four countries and 60 million people - the UK - yet would be better served by giving up lots of power to a union with 23 languages, 27 countries and 500 million people - the EU."

At Holyrood, Labour's spokesman for economy and skills, John Park, said: "His comment 'sterling is sinking like a stone' would be indefensible from a UK Government minister.

"Does he not realise such comments potentially undermine Scottish manufacturing jobs? He seems unable to take on board his responsibilities for Scotland as part of the British economy."

Last week SNP MSP Willie Coffey urged shops, pubs and restaurants to accept euros over the counter from visitors coming to Scotland during this year's Homecoming events.

Thousands of visitors are expected for festivities to mark the 250th anniversary year of the birth of poet Robert Burns.