Berlin: British Prime Minister Tony Blair said yesterday that the European Union would eventually have to face the fact that it could not continue with its current set of rules.

Blair said after talks with German Chancellor Angela Merkel that despite the rejection of the proposed EU constitution by French and Dutch voters last year, "we do need institutional change in Europe for Europe to work more effectively".

"There is a period of reflection now in Europe about the constitution," he told a press conference.

"At some point we will come back to the fact that a Europe at 25 or 27 [member states] cannot work effectively with the rules we have in place at the moment."

The EU constitution is designed to provide a legal framework for the bloc which enlarged in 2004 from 15 to 25 members, opening its doors to eastern European states.

Blair said the question facing Europe now was to reconcile the rejection of the constitution by two of the EU's key members with the fact that a new structure was needed.

"I don't think there is any point in speculating what may happen because we can't be sure at this moment," he added.

The constitution has not been put to a referendum in Britain, but Germany has been one of the strongest supporters of the treaty and both houses of parliament endorsed it last year, although it was not put to a public referendum.

Merkel and Blair also agreed that Europe needs to develop a common energy policy for the next 15 years, including researching renewable sources and raising its bargaining power with the outside world.

"We should put the question of a common energy policy and common energy concepts on the agenda within the European Union," Merkel said.

Both leaders wanted to discuss this at the bloc's next summit in March, she added.