Prime Minister David Cameron's wheeze of dangling the distant promise of a referendum on EU membership by 2017 will face challenges in the Commons today.

Mr Cameron has urged his MPs to back a private member's Bill introduced by Tory backbencher James Wharton that demands an EU referendum before December 2017.

But millionaire Tory rebel Adam Afriyie MP has threatened to move an amendment demanding a referendum by October 23 2014 - before the next election.

Tory whips are alarmed that a lengthy debate on the Windsor MP's amendment could scupper the Bill during today's report stage proceedings.

To add to Mr Cameron's woes, some pro-EU Labour MPs have tabled a host of amendments to the Bill.

Ilford South MP Mike Gapes has tabled no fewer than 53 amendments.

Cross-party People's Pledge co-founder Stuart Coster scolded MPs who are trying to scupper the Bill.

"We are urging MPs to unite behind the Bill, to back it unamended and send it to the House of Lords with the strong approval of the people's representatives," said Mr Coster.

"Committing all parties as far as possible to holding an EU referendum by the end of 2017 is the big prize offered by James Wharton's EU Referendum Bill."

Labour shadow Europe minister Gareth Thomas punctured Mr Cameron's EU balloon by securing parliamentary answers revealing that government departments have made no provision whatsoever for the possibility of Britain voting No in a referendum.

The Ministry of Defence admitted that "the department has not made any plans for the UK's withdrawal from the EU."

Similar answers came from the Department for the Environment and the Department of Energy.