David Cameron is facing growing pressure from within the Tory ranks to stage a referendum on Britain's future in the Europe Union.
Mark Pritchard, the secretary of the influential Tory backbench 1922 Committee, has warned that Conservative MPs "can no longer be taken for granted" on the issue.
Writing in The Daily Telegraph, he described membership of the EU as a "burdensome yoke, disfiguring Britain's independence" and called for a referendum on forming a "trade-only relationship" with the Brussels bloc.
His intervention comes amid growing frustration among Tory eurosceptics at the failure so far of the Government to repatriate powers from Europe in the face of entrenched opposition from their Liberal Democrat coalition partners.
Last week 120 Conservative backbenchers gathered at a private meeting in Westminster to voice their impatience at the lack of progress on the issue - a theme certain to surface again at the party's annual conference next month in Manchester.
Lib Dem Treasury Chief Secretary Danny Alexander risked further inflaming opinion on the Tory benches, telling his party's conference in Birmingham that the "anti-Europeans" were the "enemies of growth".
In his article, Mr Pritchard wrote: "Conservative backbenchers can no longer be taken for granted. Conservative MPs will not continue to write blank cheques for workers in Lisbon while people in London and Leicester are joining the dole queue.
"For many Britons, the EU has already become a kind of occupying force, setting unfamiliar rules, demanding levies, curbing freedoms, subverting our culture, and imposing alien taxes.
"In less than four decades, and without a single shot being fired, Britain has become enslaved to Europe - servitude that intrudes and impinges on millions of British lives every day. Brussels has become a burdensome yoke, disfiguring Britain's independence and diluting her sovereignty."
He described his proposal for a referendum on whether Britain should be part of a political union or a trade-only relationship as "a moderate proposition that would attract voters from across the political spectrum".