The impact of European Union legislation on Britain is to be subjected to a comprehensive Whitehall audit that will inform future debate about the need for a referendum, Foreign Secretary William Hague said.
The audit will cover all aspects of EU legislation and its implications for the British national interest, he told MPs. While it will not directly address the case for a referendum, Mr Hague said, it would be "immensely useful" for those engaged in the debate.
The announcement comes as Prime Minister David Cameron is under growing pressure from increasingly-mutinous Tory backbenchers to hold a referendum on Britain's relationship with the EU. But it fulfils a long-standing commitment from both the Conservatives and Liberal Democrats in the 2010 Coalition Agreement, which promised to "examine the balance of the EU's existing competences".
Mr Hague stressed that it would provide "evidence and analysis" and leave to the political parties questions of policy. It will be complete for 2014, the year before the scheduled next general election.
"The end result will be the most thorough and detailed analysis possible on what the exercise of the EU's powers does and what it means for the United Kingdom," he said in a statement to the Commons. "The review will present the evidence and analysis, and it will be, of course, for political parties to decide on their own policy recommendations.
"Such a comprehensive piece of work has never been undertaken before but is long overdue. It will ensure that our national debate is grounded in knowledge of the facts and will be a valuable aid for policy makers in the future."
Staunch Tory eurosceptic Bill Cash welcomed the review but called for it to consider "the necessity for a referendum as soon as it can possibly take place".But Mr Hague said it was "for each political party to explain the circumstances in which they will hold referendums".
"This is not about a referendum. Questions about a referendum are separate questions from this, although I also believe that in any future public debate or referendum of any kind about the European Union, this exercise having been conducted will be immensely useful for the public, for parliament, for all involved in that debate."
Shadow foreign secretary Douglas Alexander suggested the announcement had been made because of the Government's "political problems". The Prime Minister sought to mollify Tory eurosceptics earlier this month by saying he was open to the idea of an EU referendum but not until he had had the opportunity to win back powers from Brussels.
That failed to reassure at least some of his MPs, however, who criticised his position as "jam tomorrow". He is facing further disquiet from his backbenchers over plans to reform the House of Lords, with 91 Tories rebelling against the legislation this week.