David Cameron will hold talks with key players in Brussels on a hastily-arranged visit to discuss his demands for changes to the European Union.
The Prime Minister cancelled a planned trip to Sweden and Denmark in order to meet European Commission president Jean-Claude Juncker to discuss his renegotiation, with plans for an "emergency brake" to prevent EU migrants claiming benefits set to be on the agenda.
Mr Cameron will also hold talks with European Parliament president Martin Schulz in the Belgian capital as he continues his diplomatic push ahead of a crunch meeting of EU leaders on February 18.
On Thursday the Prime Minister said the proposed emergency brake mechanism to ease pressure from migrants shows Europe is "taking on board" his concerns.
But he insisted his own plan for an outright four-year ban on migrants claiming in-work benefits remained on the table unless something "equally potent" was proposed.
He said there was a "lot of work to be done" ahead of the February summit, not just on measures aimed at curbing the pull factors driving migration to the UK but also his demands on sovereignty, competitiveness and protection for non-euro countries.
Mr Juncker is expected to give details of the emergency brake, which reports suggest would see EU migrants barred from claiming benefits for four years when public services are deemed to be under strain.
It is not clear whether EU officials would need to give permission for the emergency brake mechanism to be used.
Mr Cameron's efforts to win support for his plans will continue over the coming weeks, with European Council president Donald Tusk visiting Downing Street over the weekend and the Prime Minister due to travel to Germany on February 12.
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 this 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.