David Cameron has said Jose Manuel Barroso should start "respecting" the Conservative Party instead of "trying to lecture them" in response to Mr Barroso's claims that the Tories were heading for defeat at the hands of Ukip in next year's European elections.
"The Barroso thing did annoy me because, frankly, his job is to serve the members of the European Union and the British Conservatives in the European Parliament are an important party," Mr Cameron said on LBC.
"They are the governing party of the United Kingdom and he should be respecting their views rather than trying to lecture them. They've got an important contribution to make and I think he got it wrong, and I'll tell him that."
The Prime Minister revealed that the pair have had "some pretty robust exchanges" in the past, and suspected the conversation about Mr Barroso's comment would be one of them.
Continued hostility to the European Union could put years of peace in Europe at risk, according to the President of the European Commission.
In his State of the Union speech, Jose Manuel Barroso hailed European integration as "the valid answer" to the wars of the 20th century:
"Let me say this to all those who rejoice in Europe's difficulties and who want to roll back our integration and go back to isolation: the pre-integrated Europe of the divisions, the war, the trenches, is not what people desire and deserve.
"The European continent has never in its history known such a long period of peace as since the creation of the European Community. It is our duty to preserve it and deepen it."
Mr Barrasso also warned that the increasingly anti-European stance adopted by the Conservative party could help Nigel Farage's Ukip beat them in the May 2014 polls as voters will have to choose between "the original and the copy" and "prefer the original".
At the G8 Summit José Manuel Barroso, President of the European Commission, has been speaking about the financial turmoil in the EU.He said the wounds caused by the political crisis are not yet healed and that European need to take action for growth while putting public finances in order.
He said this is the only path to sustainable growth and that a confident G8 summit will recognise this. He emphasised the growing awareness in Europe of the need to combine fiscal consolidation with structural reform.
Turning to the issue of Greece's existence within the Eurozone he said Europe wants Greece to stay in the Euro area and that Greece is part of the Euro family. But he stressed that the nation must fulfill its commitments for its loan program.