26/03/2015 07:22 GMT | Updated 26/03/2015 07:59 GMT

Owen Paterson Warns Fellow Eurosceptics Britain Would Vote To Remain Part Of The EU

Dominic Lipinski/PA Wire
File photo dated 20/06/13 of former environment secretary Owen Paterson, who has urged David Cameron to outline the "optimistic destination" the UK is heading for as he tries to renegotiate powers back from the EU.

Britons would choose to stay in the European Union if a referendum were held today, a key eurosceptic Conservative has warned those in favour of exit.

Owen Paterson, David Cameron's former environment secretary, said that those, like him, agitating for the United Kingdom to leave the EU needed more time to persuade voters it was a good idea.

The prime minister has pledged he will quit as prime minister after the election if he is unable to secure an in/out EU referendum by 2017.

Paterson told an audience in Washington DC on Wednesday: "At the moment, I think you would lose an 'out' referendum because it has not been explained, the optimistic vision I have. And out is frightening, it's unknown and people will hang onto nurse."

"My view is we have to go the whole hog, get back to the trade arrangement, but we need time to explain there is a positive destination. I think we have the most spectacular future outside the political and judicial arrangements [of the EU], embracing the trade, commercial and economic aspects," he said. "But at the moment that has not been explained."

Paterson told The Heritage Foundation think-tank that he wanted Britain to remain part of a European free-trade zone but leave the political bloc.

"There is a protest party, Ukip, that has done no absolutely no work on the detail [of how to leave] and they are being attacked, quite rightly, for that because their image is backward looking and negative," he explained to his American audience.

The former cabinet minister, who is seen as harbouring leadership ambitions, said voters still saw leaving the EU "to be a frightening leap in the dark".