Speaking to the European parliament about the EU migrant crisis and UK membership, Juncker said: "We want a fair deal with Britain, and we are working in that direction. I cannot give details, but our negotiation teams are in close contact". Juncker added:
It takes two to tango. We have to dance and our British friends have to dance. I am 150 per cent in favour of having Britain as a constructive member state of the European Union.
We need Britain. Personally I don't think Britain needs the European Union.
The comments will be seized on by the "Out" campaign, which launched last week. This week the pro-"In" campaign launched.
Juncker's comments came ahead of a meeting with Prime Minister David Cameron on Thursday, in which the two will discuss the Prime Minister's renegotiation.
Cameron has promised an In/Out referendum before the end of 2017, with polls narrowing between the two sides.