THE Queen may not remain head of state in an independent Scotland after one of the Scottish National Party's most senior MPs confirmed it is party policy to hold a referendum on the monarchy.

Christine Grahame, the convener of the Scottish Parliament's justice committee, said the party has pledged to hold a public vote on a separate Scotland having a ''full-blown monarchy, an edited version or go for a republic''.

Outlining her support for the latter, she attacked the public reaction to the Princess of Wales's death as ''complete strangers lemming-like threw themselves into publicity-driven grief''.

She said an indifferent public are now ''spoon-fed the William and Kate show, the latter ironically committed like her deceased predecessor to remaining stick thin for photogenic reasons''.

Ms Grahame insisted she bears no personal ill feeling towards the royal family, but said that ''as a Scot'' she was upset the department store John Lewis was stocking Union Jacks to celebrate the diamond jubilee.

Her comments seriously undermine Alex Salmond's claim that the Queen and her successors would automatically remain head of state following separation from England.

The First Minister has pledged to retain great British institutions like the monarchy and the pound in an attempt to persuade sceptical Scots to support separation in the forthcoming referendum.

But despite him repeatedly lavishing praise on the Queen, the SNP cannot produce any evidence that members have voted to replace their long-standing policy that a referendum would be held on the monarchy after independence.

The Tories said this raised the prospect of the SNP replacing the Queen as soon as separation had been achieved or Mr Salmond stepped down as party leader.

Writing for a left-wing journal, Ms Grahame said her republican views were shared by some of her SNP colleagues but were not official party policy.

''The last time I looked at that, after independence there would be a referendum at some point on whether we in Scotland have the full blown monarchy, an edited version or go for a republic. I have no problems with that, being a wholehearted democrat,'' she wrote.

In the same journal, Angus MacNeil, the SNP's Western Isles MP, made the case for the Queen staying head of state by arguing that a debate over the monarchy would be a ''silly distraction from the independence debate''.

Telegraph, London