David Cameron will drop within days his pledge to hold a referendum on the Lisbon treaty, The Times has learnt.

The Conservative leader is preparing to set out a fresh stance on Europe that will involve promising in his election manifesto to “repatriate” certain key powers from Brussels.

He will also pledge to write into law that no British government will ever again be able to push through a European treaty without a referendum.

Mr Cameron began preparing yesterday for what diehard sceptics will see as a climbdown. He acknowledged openly for the first time that his party may not be able to hold a promised referendum on the treaty before it becomes law. That is because President Klaus of the Czech Republic is on the point of ending his last stand, which has delayed the final ratification of the Lisbon treaty.

The Czech constitutional court is expected to rule today that concessions won at the European summit in Brussels on Friday will protect the country’s sovereignty, meaning that there is now no obstacle to it going through. As soon as Mr Klaus has indicated that he will sign the treaty, Mr Cameron is likely to unveil his long-awaited new policy.

He will not necessarily wait for Mr Klaus to append his signature, and his statement could come this week. By seeking a mandate in the manifesto to “repatriate” powers in areas of employment, justice and home affairs, Mr Cameron will be able to avoid a “pre-negotiation” referendum if he is elected.

Yesterday he said that the party would “do what we can to make good all our promises”, but refused to spell out his post-ratification stance.

Speaking at the Royal College of Pathologists, he said: “We would address that just as soon as we need to. What I said is that we would hold that referendum on the Lisbon treaty but it seems we are getting close to a point when it is part of European law.”

Mr Cameron, who wrote to Mr Klaus last month, said: “I had always hoped that President Klaus wouldn’t sign but it seems that times are changing.”

Bill Cash, the leading Conservative Eurosceptic, said that a referendum should be held in Britain regardless of whether the Czech Republic had ratified the treaty.

He said: “As David Cameron has said, we need an association of member states. In order to achieve this, we cannot simply cherry-pick individual aspects of the treaty and call for renegotiation of those.

“We need a full referendum on Lisbon as we were promised and as we voted in the House of Commons. No ifs or buts.

“This is about the Government of the United Kingdom operating in line with the democratic wishes of the electorate.”

In 2007, at a time when Gordon Brown’s fortunes were riding so high that there was talk of a snap election, Mr Cameron promised a referendum “on any EU treaty that emerges from these negotiations”.

But for some time the party leadership has prepared the ground for a retreat, believing that if elected it will have far larger priorities than a referendum campaign over a treaty that has been ratified.

Yesterday No 10 continued to back Tony Blair for the job of EU president, and insisted that it was not lobbying for David Miliband, the Foreign Secretary, to become EU foreign affairs chief. Mr Miliband has also assured No 10 that he is not seeking that role, The Times has learnt. “He is saying to us in private what he has said in public about not being available for the job and wanting to carry on as Foreign Secretary,” an insider said.

Mr Brown’s spokesman said: “He remains absolutely of the view that, if Tony Blair wishes to be a candidate, he would be the right candidate. The Prime Minister is four — if not five — square behind him.”

Times Recommends

• How I lost the gift of joy for a while
• Why Ann Widdecombe has got it wrong
• Alas, it’s the end of the road for petrolheads