British lawmakers will on Friday vote on whether to move the country a step closer to an in-out referendum on its membership of the European Union by 2017.
Hundreds of MPs are expected in parliament for the second reading of a bill brought by a eurosceptic lawmaker from Prime Minister David Cameron's Conservative Party.
Cameron last month ordered all Conservative lawmakers to give their full backing to the bill, which was rushed out in May in a bid to satisfy the increasingly rebellious eurosceptic wing of the party.
Tory MP James Wharton confirmed he would table the centre-right party's bill after he came top of a ballot to see which lawmakers may put forward so-called private members' legislation.
Parliament will now formally debate the draft bill, although under the complex British parliamentary system there is no guarantee that it will reach a vote or become law.
In January, Cameron vowed to renegotiate Britain's troubled relationship with the European Union and then hold an in-out referendum by the end of 2017, provided that he wins the next general election in 2015.
But disgruntled Conservative eurosceptics want him to enshrine that promise in law before the election to stop any backtracking, as well as to head off the rise of the anti-EU UK Independence Party (UKIP).
Backers of the bill admit it faces difficulties as it will likely be opposed by the Liberal Democrats, the pro-EU junior partners in Cameron's coalition government, and by the opposition Labour party.
But The Guardian newspaper reported last week that Labour was contemplating going even further by proposing an amendment calling for an in-out vote before the 2015.
The bill requires a referendum to be held before December 31, 2017, on the question: "Do you think that the United Kingdom should remain a member of the European Union?"
Wharton is bringing the bill as the Liberal Democrats would block any government attempts to table the legislation.
However, private members bills often fail due to time constraints and Wharton himself warned that any amendments would likely kill the bill.
The issue of Europe has long been toxic for the Conservatives, leading to the downfall of late prime minister Margaret Thatcher in 1990 and weakening her successor John Major.
Cameron came into office in 2010 telling the Conservatives that they were alienating voters by "banging on" about Europe but has since faced three parliamentary rebellions on the issue.