EU Referendum bill: Martin Horwood and James Wharton
8 November 2013 Last updated at 14:40 GMT
Conservative MP James Wharton said his bill was the "best chance of delivering a referendum" on Britain's membership of the EU.
MPs have tabled a series of amendments to the bill, including one asking whether residents of Gibraltar and prisoners should be able to vote in a referendum, and another by Tory backbencher Adam Afriyie calling for a vote to be held before 2015.
Lib Dem MP Martin Horwood said his party was "not afraid of a referendum" as the pair spoke to Andrew Neil on BBC2's Daily Politics.
Mr Wharton's bid for a referendum by 2017 is backed by David Cameron, but opposed by his deputy Nick Clegg and opposition leader Ed Miliband.