David Cameron is to call a special meeting of Cabinet on Saturday to approve a deal struck with fellow EU leaders in Brussels which will pave the way for an in/out referendum on British membership by the summer.
The historic poll is expected to be held on June 23 after the Prime Minister hailed an agreement which he said would provide "special status in the EU" and left no doubt that he will lead the campaign to keep Britain in the EU.
The development came late on the second day of gruelling talks in Brussels between leaders of the 28 member-states, which saw the Prime Minister face opposition to proposals to restrict migrant benefits and provide new protections for countries outside the single currency.
The new deal provides for a seven-year emergency brake on in-work benefits for EU migrant workers, as well as cuts in child benefit for their children living overseas - applicable immediately for new arrivals and from 2020 for the 34,000 existing claimants.
It also says that EU treaties will be amended to state explicitly that references to the requirement to seek ever-closer union "do not apply to the United Kingdom".
A jubilant Mr Cameron tweeted from the room where round-table discussions took place: "I have negotiated a deal to give the UK special status in the EU. I will be recommending it to Cabinet tomorrow."