The British are only "part-time Europeans" and never wanted to share all policies decided by the European Union, Jean-Claude Juncker has claimed
The President of the European Commission added that no one would benefit from Britain leaving the EU.
"The British since the very beginning were part-time Europeans. What we need are full-time Europeans," he told Euronews in an interview.
"The British were told for more than 40 years that they were in but they didn't want to share all the policies that have been decided," he added.
Asked who he thought would benefit from Brexit, Juncker said that Brexit would be a "lose-lose situation" for both the UK and the EU.
And he also criticised the decision to hold a vote in the first place, claiming it was a "mistake" to put the question to a referendum.
However, he said that despite the current political deadlock in the UK, he said he still thinks that Britain wants to leave the EU.
Mr Johnson will meet European Commission President Jean-Claude Juncker on Monday for talks.
The Prime Minister’s confidence came despite MPs earlier this week passing a law ruling out a no-deal Brexit and asking for an extension unless he can get a deal with Brussels before the October deadline.
During his interview with Euronews, Mr Juncker was also asked whether he believed there was "a special place in hell for those who promoted Brexit", echoing comments made by European Council President Donald Tusk.
However, Juncker said he did not believe in hell.
"I wouldn't put someone in hell because they were doing their best, mainly Theresa May," he said, adding that they negotiated not a "deal" with May but a "treaty".
He said he would've liked for the British parliament to accept the Withdrawal Agreement, adding that "things would be easier" now.