David Cameron knows he must deliver "significant return of powers" from the EU to win the support of Tory colleagues in a referendum on British membership, Iain Duncan Smith has indicated.
The Work and Pensions Secretary said the Prime Minister was clear he could not "come back with nothing" from a mooted renegotiation after the general election.
He also lashed out at the BBC for failing to give enough prominence to Mr Cameron's promise of an in-out vote in 2017.
Speaking to the Sunday Telegraph, Mr Duncan Smith said: "I don't think the Prime Minister in any way is lost on that fact that he will need to get back some substantial and significant return of powers".
More top news
British hopes for a sunny Easter break have been dealt a blow with forecasters warning of a week of wind, rain and even snow.
More than one in five school staff have had a false allegation made against them by a pupil, according to a survey.
Parents of obese children rarely spot that their child is overweight, doctors warn.