David Cameron has defended his plans to renegotiate ties with Brussels, insisting it would be a "great prize" for the UK to remain in a reformed European Union.
The Prime Minister insisted it was right to prevent Eurosceptic ministers from campaigning for "Brexit" until the negotiation process was complete.
He stressed his Government was "not neutral" about the outcome it desired and all members of the Cabinet were signed up to the plan.
But he acknowledged that some members of his team had "long-standing views" about Europe and would be allowed to campaign in a "personal capacity" for a British exit.
Answering questions following a speech in Islington, north London, he said: "The Government is not neutral in some great debate about the future of our country.
"The Government has a very clear policy, which every member of the Government has signed up to, which is that we are going to conduct a renegotiation about Britain's place in Europe, with very clear goals. We are going to carry out a referendum and we are aiming to achieve Britain in a reformed European Union.
"That is the policy which they are all working towards, a policy I hope will be successful, we will have those discussions in February.
"At that moment, people who have long-standing views will be able to campaign in a personal capacity."
The UK's demands are to be discussed in crunch talks involving the EU's leaders at a summit in Brussels next month.
Mr Cameron said there was a "great prize for Britain" at stake in "knocking on the head the things that have been driving us up the wall" about the EU.
"That's the prize that the Government is aiming for," he said.