Foreign Secretary William Hague has issued a fresh warning to Tory Eurosceptics that demands for Parliament to be able to veto all laws coming from Brussels are unrealistic.
Ninety-five Conservative backbenchers have signed a letter calling for Parliament to be able to block any aspect of European Union legislation.
Mr Hague said that, while he believed that national parliaments in the EU should have greater powers, giving individual parliaments the right of veto would undermine the single market.
"What you can't have in any system that relies on some common rules - even in a free trade area that relies on common rules - is each of the parliaments being able regularly and unilaterally to say we are not applying this or that just by our own decision," he told the BBC Radio 4 Today programme.
"Clearly a single market or a free trade area would not work on that basis. Even the Swiss or Norwegian arrangement with the European Union couldn't work on that basis so we have to be careful what we support.
"But the direction of greater power for national parliaments and reducing, relatively speaking, the power of the European Union vis a vis national parliaments is something I very strongly support."
His comments were echoed by former Italian prime minister Mario Monti, who said Britain would be among the big losers if the single market was undermined.
"A country like the UK in particular relies heavily on a smoothly functioning single market across Europe," he told the Today programme.
"If each parliament in each member state were to be able to tear apart small bits, or big bits even, of the single market legislation, then this would be a patchwork, not a market. One of the countries that would suffer most is indeed the UK."
Mr Monti warned that Britain would find itself in a "pretty, pretty cold" place if it was to vote to leave the EU in Prime Minister David Cameron's promised referendum after the next general election.
"If the British people were to exercise their duress, their toughness, in one point in time on occasion of the referendum then they will be either in or out and out there it will be pretty, pretty cold," he said.