Scottish independence: Castle launch ‘sends out wrong messages’ claim rivals

But castle officials have insisted today’s event in the Great Hall is “legitimate” government business.

The last Labour administration used the castle to launch the Scotland Bill that brought about the devolution settlement in 1997.

Liberal Democrats leader Willie Rennie said Scots would not be happy with Mr Salmond’s venue choice. “This sends all the wrong messages,” Mr Rennie said.

“Things seem to have gone to the First Minister’s head. To use Scotland’s national monument for party political ends will just jar with people.”

Labour MSP Kezia Dugdale said: “Edinburgh Castle is a proud symbol of Scotland and belongs to all of the people of Scotland – not Alex Salmond or the SNP.

“It is disappointing that Historic Scotland has allowed this venue to be used for such overtly political purposes.”

Tory chief whip John Lamont said: “It is not acceptable for him to abuse his right to use them in such a manner, especially as Edinburgh Castle is one of Scotland’s most treasured landmarks.

“Instead of attempting to move his office into the castle he should come back down to earth and start concentrating on getting Scotland working again.”

A spokeswoman for Historic Scotland, which runs the castle, said ministers may use it to promote or deliver government business.

“The press conference relating to the launch of the referendum consultation is a legitimate part of government business,” she said.

“Our sites are often used as venues for government events and announcements. For example, in July 1997 the White Paper on the Scotland Bill was launched at an event in Edinburgh Castle.”

Mr Salmond staged a St Andrew’s Day bash at the castle last year and hosted China’s vice-premier Li Keqiang at a state dinner.

• Scottish diaspora

Despite being open to anyone, the consultation will be of particular interest to the millions of people who are either Scots-born living abroad or part of the country’s global diaspora.

An estimated one million Scots-born people live outside Scotland, but those who feel they have Scots ancestry, has been estimated as high as 40 million.

In the 2000 US census, 4.8 million Americans reported Scottish ancestry. Scottish-Canadians are the 3rd biggest ethnic group in Canada where 4.7 million citizens claim roots.

Several more significant numbers of Scots have emigrated Down Under over the generations to Australia and New Zealand. Scots have also been emigrating to mainland Europe for centuries as merchants and soldiers to countries including France, Poland, Italy, Germany, Scandinavia, and the Netherlands.