ENGLISH votes for English laws, supported by Conservatives as an answer to the West Lothian Question, could threaten the continued existence of the United Kingdom, according to one of Britain's leading constitutional experts.

Professor Vernon Bogdanor, of King's College London, has argued that English votes for English laws (EVEL) could have a "separatist effect", which is why, he says, the SNP is in favour of it.

In his submission to the McKay Commission, which is examining the West Lothian Question, the academic makes it clear that it cannot be answered under the current system of asymmetrical devolution.

He dismisses the idea of an English Parliament, noting how there is "no federal system in the world in which one of the units represents over 80% of the population".

Mr Bogdanor says the effect of EVEL would be that whenever a government depended upon Scottish MPs for its majority, as in 1964 and 1974, the Commons would take on a dual personality.

"There would be in such circumstances a UK majority – presumably Labour – for foreign affairs, defence, economic policy and social security but an alternative majority without the Scots – presumably Conservative – for health, education and other matters devolved to Scotland."

He said it would be difficult to see how Britain could be effectively governed.

The academic suggests there might be a political solution to the conundrum – the Conservatives gain more seats in Scotland or proportional representation is introduced.