The Chancellor also made clear that if the UK were unable to secure support for reform from all 28 member states, then it was ready to press ahead with a smaller group of like-minded countries under what he termed "enhanced co-operation".
He claimed EU treaties were no longer "fit for purpose" and failure to reform would condemn the continent to a future of economic crisis and decline. The broadside came as a letter signed by 95 Tory backbenchers earlier this week called for a Westminster veto on all EU legislation.
But Conservative former minister Tim Loughton, a member of the Fresh Start group pressing for EU reform, dismissed the letter as "something of a sideshow", stressing the UK's relationship with Europe "won't be up to those 95 MPs, whoever they may be", but the Briton's voting in the referendum in 2017.
Labour's Douglas Alexander said: "The Conservative leadership seems to be spending more time negotiating with their backbenchers than with Europe."