David Cameron is to hold talks with European Council president Donald Tusk and fly to Germany to make a keynote speech on Britain's future in Europe, as he fights to keep his renegotiation on track.
The Prime Minister announced on Wednesday that he was scrapping a planned visit to Scandinavia in order to travel to Brussels on Friday for hastily arranged discussions with European Commission president Jean-Claude Juncker.
Now Downing Street has revealed the Juncker meeting will be followed by a Downing Street dinner with Mr Tusk on Sunday. Mr Cameron will then fly to Hamburg on February 12, where he will have the opportunity to discuss his plans with Chancellor Angela Merkel as he delivers a speech on EU reform to the annual St Matthew's Day banquet.
Mr Tusk is due to publish "concrete proposals" for dealing with the UK's demands within the next couple of weeks, ahead of a crunch summit on February 18-19 at which Mr Cameron hopes to secure agreement with the 27 other EU leaders on a package of reforms.
Downing Street denied that the flurry of meetings were an indication of concern within Number 10 that the PM's timetable for an in/out referendum may be slipping.
Foreign Secretary Philip Hammond has admitted that a referendum before the summer will be difficult if no deal is struck at the February summit, and "impossible" if it is not agreed at the following meeting in March.
A Number 10 spokesman said: "I would take all of this as further evidence of the desire to continue the renegotiations, to continue meeting with leaders across the EU to work towards getting the best possible deal for the British people.
"As the Prime Minister has said on many occasions, we are working towards February, we would like to get a deal in February, but ultimately we want the best possible deal and if we don't get it in February we will wait until the next time ... The only deadline we are working towards is the end of 2017."
The spokesman declined to say whether Mr Cameron or Mr Tusk requested Sunday's meeting.