Tony Blair has said Germany's presidency of the European Union would give rise to "challenging discussions" on the future of the constitution.
The Prime Minister's comments came as German Chancellor Angela Merkel set out to revive the controversial document which was rejected by French and Dutch voters in 2005.
Speaking alongside the French Prime Minister Dominique de Villepin, Mr Blair said that they would be discussing Germany during bi-lateral talks.
Mr Blair said: "The new German presidency is very important and will lead to, I think, some very interesting and challenging discussions around economic reform and (the) constitution and so on."
Earlier, Mrs Merkel made clear the process of revival was her EU presidency priority between now and the summer.
Kicking off Germany's six-month presidency of the EU, Mrs Merkel told MEPs in Strasbourg her goal was to present a revised constitution and a timetable for agreement to a summit of European heads in June.
The constitution would put a "lumbering, bureaucratic, divided" Europe back on course, she said, warning that failure to find common ground by the next EU elections in 2009 would worsen its plight.
Constitution supporters have refused to admit defeat on the issue following the referendum defeats 18 months ago and Mrs Merkel's comments will give them renewed hope.
Downing Street stressed the need to consider the position "on the ground" in an apparent reference to public opposition to the constitution. Refusing to be drawn on whether the Government stood by its commitment to hold a referendum if there was a new constitution, the Prime Minister's official spokesman said: "Let us take this step by step.
"Obviously, the first step is to try to reach a consensus on the way forward. That has to bear in mind not just the position of the presidency, although that is important, but also the position on the ground - in France and Holland, first of all."
