Conservative proposals for dealing with the 'West Lothian question' have been criticised by the prime minister and Labour MPs.

There have recently been suggestions the Tories will pursue a policy of only allowing English MPs to vote on laws that are limited to England.

The question arises from the current arrangements that allow Scottish MPs to vote on matters such as the health service and schools in England, although health and education are subjects decided by the devolved administration in Edinburgh.

Opening Wednesday's prime minister's questions, Labour MP George Howarth took a dig at the apparent Conservative position by asking if the government would consider banning London MPs from voting on issues not affecting the capital given it now had its own assembly.

Tony Blair said: "I think it's important that we have one class of member of parliament, I think that's an essential part of our constitution."

The prime minister said the idea of English votes for English issues was "wholly contrary to the spirit of our constitution and wholly the wrong thing to do".

Scottish Labour MP Mohammad Sarwar later raised the issue again, prompting the prime minister to say the government would never make such a change.

The subject was earlier discussed at Wales Office questions, when Labour MP Ian Lucas said: "Members of my constituency in Wrexham are treated in English hospitals.

"Will my honourable friend give me an absolute assurance that we will support my right to ask questions on their behalf?"

Wales Office minister Nick Ainger said the Conservative idea was "outrageous".

"The party opposite intends to treat Welsh and Scottish MPs as second class citizens," he said.