Prime Minister David Cameron will finally deliver his long-awaited speech on Britain’s future in the European Union in London tomorrow.

Mr Cameron was forced to calloff plans to make the address – at least six months in the preparation – in Amsterdam last Friday because of the hostage crisis in Algeria.

Extracts released last week showed that he will use the speech to warn EU leaders that Britain could leave the 27-nation bloc if three key concerns are not resolved.

But his official spokesman declined to comment yesterday on weekend press reports that he will announce an in/out referendum to be held after the 2015 general election, but rule out legislation during this Parliament.

According to advance extracts released last week, Mr Cameron will warn that Britain could “drift towards the exit” from the EU unless there is real change in Brussels.

He identified the crisis in the eurozone, the challenge of economic competitiveness and the issue of democratic legitimacy as key issues which must be resolved in negotiations on the future shape of the EU.

Mr Cameron has indicated he wants to renegotiate the UK’s relationship with the EU and then seek “fresh consent” for the new arrangement from the British people – probably through a referendum. He has yet to make clear what the terms of the referendum would be. Downing Street said last week that the Netherlands was an “entirely appropriate” place for Mr Cameron to set out his vision for the future of the EU, as it was a founding member and shared Britain’s free-trading history.

The choice of venue continued a tradition of keynote speeches on Europe being made in continental cities, dating back to Winston Churchill’s 1946 “United States of Europe” address in Zurich, Margaret Thatcher’s euro-sceptic Bruges speech in 1988 and Tony Blair’s 2005 address to the European Parliament in Brussels.

It is understood that Mr Cameron planned to give the speech in Amsterdam tomorrow, but had to abandon that date because it clashed with German and French celebrations of the 50th anniversary of the 1963 Elysee Treaty.