Nicolas Sarkozy has withdrawn his backing of Tony Blair to become the first president of the European Union, senior sources have told the BBC.
The French president is understood to have changed his mind after meeting German Chancellor Angela Merkel.
It is thought he feels EU opposition to the former UK prime minister is too strong because he backed the Iraq war.
The president will be chosen by leaders of EU member states. The post was created under the new EU reform treaty,
The sources close to the president also indicated that Mr Sarkozy felt Mr Blair was not right for the role because Britain has failed to adopt the European single currency and the Schengen zone of passport-free travel.
Instead, the sources say the top job could go to the current president of the commission, Jose Manuel Baroso, or the prime minister of Luxembourg, Jean-Claude Juncker.
BBC Europe editor Mark Mardell however said the British government has a distaste for Mr Juncker, who is seen as far too keen on more European integration, and British prime minister Gordon Brown would probably veto him.
He added that some of the smart money was moving to the Danish prime minister Anders Rasmussen.
The new president is to chair EU summits, take on some of the functions of the current presidency of the Council of the European Union - held on a rotating six-month basis by EU heads of government - and represent the EU on common foreign and security policy.