Scots would be forced to leave the EU if the English vote for exit, the Tory backbencher spearheading a membership referendum Bill has warned.

James Wharton also denied that the vote could provoke a constitutional crisis.

Polls suggest that there is more support for EU membership in Wales and Scotland than in England.

Mr Wharton said he would be surprised if there were vastly different outcomes in different parts of the UK.

But he insisted that if Scotland plumped to stay and England to leave, the outcome would not pose a problem.

"I don't see why it would be a constitutional crisis," he said. "We are a United Kingdom. We would have one electorate that could vote on that. I would be surprised if we got huge discrepancies in the result and even if we did, that would be ultimately the will of the people of the United Kingdom.

"This is an issue that affects the country as a whole. Whilst we do have a devolved government in Wales and Scotland, this is an issue of foreign affairs and sits still in Westminster, and rightly should.

"I don't think it will cause a constitutional crisis."

Later this week, huge numbers of Tory MPs are expected to back Mr Wharton's Bill.