UK and and EU negotiators are not making "huge progress" in their pre-referendum talks, European Commission president Jean-Claude Juncker has said.
Speaking in the European Parliament, Mr Juncker said he and the EC wanted "a fair deal with Britain".
But, he said: "I can't say that huge progress has been achieved, I can't say that nothing has been achieved."
With David Cameron seeking to reform the UK's relations with the EU, Mr Juncker said: "It takes two to tango."
His comments sparked a debate, with some claiming he then said Britain "does not need" the EU but his spokeswoman said he had been "misheard".
Mr Juncker had in fact said "I personally do (not don't) think Britain needs Europe", she said. (You can watch the words on this Twitter clip.)
'We have to dance'
Mr Cameron wants to reform the UK's relationship with the EU ahead of an in-out referendum by the end of 2017.
He has not set out his demands in detail, but they are believed to include exemption from an ever-closer union and curbs on migrants' welfare entitlement.
In his statement Mr Juncker built on his reference to "taking two to tango", saying: "And so we have to dance, and so our British friends have to dance."
The former Luxembourg Prime Minister also said he was "150% in favour of having Britain as a constructive member of the EU".
The disputed line about Britain needing Europe was seized upon by Eurosceptics, with UKIP leader Nigel Farage offering to buy him champagne.
The Vote Leave campaign said it was "encouraging" that Mr Juncker agreed the UK could "thrive outside the EU".