Work and Pensions Secretary Iain Duncan Smith has denied claims that David Cameron's European Union renegotiation is in trouble.
The Prime Minister has been forced to admit he will not be able to get a deal at this month's summit of EU leaders in Brussels, as he had previously hoped, as the scale of his demands meant it was impossible to reach an agreement "in one go".
However Mr Duncan Smith - one of the most Eurosceptic members of the Cabinet - rejected suggestions that it was a sign that Mr Cameron's negotiating strategy was crumbling.
"The delay, which everyone has said is a sign of weakness, is a sign of strength," he told BBC1's The Andrew Marr Show.
"It says the Prime Minister is determined not just to come back with any deal but to come back with a deal that he knows he can sell to the British people. That speaks volumes about his determination."
The failure to reach an early settlement means Mr Cameron will have less time to argue the case for Britain to remain in the EU in the referendum on the UK's membership, which must take place before the end of 2017.
One of the most difficult issues has been the Prime Minister's insistence on a four-year ban on claiming in-work benefits for newly arrived workers from other EU member states.
Mr Duncan Smith refused to be drawn on suggestions that ministers could get round EU objections that it is discriminatory to other EU nationals by extending it to British nationals as well.
"This has never been part of our proposal. We will wait and see what is decided," he said.
He added: "I am in the business with the Prime Minister of delivering what the Prime Minister said he wanted at the time of the election through the manifesto. What he has said clearly to his European colleagues is we need to do this."
The Work and Pensions Secretary, who is widely thought to be in favour of leaving the EU, said he would make up his mind which way to vote in the referendum once he saw what deal Mr Cameron was finally able to achieve.
"At the moment when the deal is on the table, that is when you assess whether you think it is in the benefit of Britain to stay in the EU or leave," he said.
"I have always said my judgment is that at that moment my position will become very, very clear. But it is hugely dependent on what we get back."