David Cameron will risk the ire of his European counterparts today when he attempts to further dent the chances of the lead candidate for the European Commission president.
The Prime Minister is travelling to Sweden to meet three other European premiers in a bid to derail the campaign of Jean-Claude Juncker.
Mr Juncker, a former prime minister of Luxembourg, is the favourite to land Europe's top job.
But David Cameron wants a candidate who will lead reform of the European Union and he thinks Mr Juncker fails that test.
As a long standing federalist, it's thought Mr Juncker will attempt to further integrate the EU rather than reform it.
At the summer residence of the Swedish prime minister tonight, Mr Cameron will meet Fredrik Reinfeldt of Sweden and Mark Rutte of Holland who both share Downing Street's concerns.
There the three men will attempt to persuade German Chancellor Angela Merkel of their case.
Ms Merkel has publically given her backing to Jean-Claude Juncker and the German press is fiercely opposed to any attempt by the UK and others to rock the boat.
Mr Juncker claims to have a democratic mandate as he is the favourite candidate of the largest group of MEPs in the European Parliament - the European People's party.
Attempts by David Cameron to block Mr Juncker has already caused ill feeling in many European capitals.
And he must tread a fine line. He needs support for his plans to renegotiate Britain's relationship with the EU ahead of the referendum he has promised in 2017 - should he still be Prime minister then.
But Downing Street's view, however, is that it's more important to get the right candidate in post.
It's a risky move but one the Prime Minister is convinced he must take.