UPDATED: 1:30 p.m. GMT
LONDON -- The UK is holding a referendum on June 23 to decide whether or not to stay in the European Union.
The date for the "Brexit" referendum was announced Saturday afternoon by David Cameron after he returned from 31-hour talks in Brussels seeking a deal that renegotiates Britain's status within the 28-nation bloc.
Now that the date has been set, campaigns on both sides are kicking off and ministers will start declaring what side they support. The deal will be analysed and talked about exhaustively. Cameron's own Conservatives aren't united on the issue and campaigns will watch closely which side the ministers take.
The Prime Minister convened the Cabinet at 10 a.m. Saturday to try and sell them on the deal. After the meeting, ministers were free to support the side of their choosing.
Cameron said in a statement overnight that the deal keeps the best parts of being in the EU but without the parts that don't work for the UK, and he will be campaigning "with all my heart and soul" to convince the British people to stay in the EU.
I believe Britain is stronger, safer and better off within a reformed European Union. My statement on tonight's deal https://t.co/7XCOHfQFTR— David Cameron (@David_Cameron) February 19, 2016
The deal states that the UK will not be part of an "ever closer union." The main sticking points were over whether to suspend welfare payments to workers from EU countries, and it was decided the UK will be able to apply an "emergency brake" during high levels of migration to limit benefits for four years.
The exact wording of the referendum question hasn't been agreed yet, but the Electoral Commission has proposed: "Should the United Kingdom remain a member of the European Union or leave the European Union?"
British, Irish and Commonwealth citizens over 18 who are resident in the UK, along with UK nationals who have lived overseas for less than 15 years will be able to vote in the referendum, according to the BBC. Members of the House of Lords and Commonwealth citizens in Gibraltar can vote too, unlike in a general election.
The strength of the Brexit campaign will be shaped by which political heavyweights support it. Over Friday night and Saturday morning, Chancellor George Osborne and Home Secretary Theresa May said they want Britain to stay in the EU.
But five Cabinet ministers immediately headed over to the Vote Leave campaign headquarters. Work and Pensions Secretary Iain Duncan Smith, Commons Leader Chris Grayling, Culture Secretary John Whittingdale, Northern Ireland Secretary Theresa Villiers and Justice Secretary Michael Gove made their positions clear shortly after Cameron's announcement.
The safe option is to #VoteLeave pic.twitter.com/I3CueHTsEP— Vote Leave (@vote_leave) February 20, 2016
Vote Leave campaigners say that Britain needs to "take back control" from an EU that is too slow to respond to the changing world. It says that Brussels bureaucracy is slow and expensive, and that EU regulation is costing the British economy dearly. It also says that immigration is out of control and Britain would have more control of it on its own.
We know exactly what life outside EU would look like: control of our borders, global trade deals, making our own laws. An exciting future.— Nigel Farage (@Nigel_Farage) February 20, 2016
Gove -- a close ally of Cameron -- will be campaigning to leave, in what he described in a long, impassioned statement as the most difficult decision of his political life.
"And if, at this moment of decision, I didn’t say what I believe I would not be true to my convictions or my country," he said.
Another high-profile Tory to watch is Boris Johnson, the outspoken mayor of London. He hasn't stated a position yet and no one seems to know what it would be.
The main opposition Labour Party supports remaining in the EU, with leader Jeremy Corbyn saying that staying is in the best interests of Britain.
.@jeremycorbyn on Labour's position on #euref #LabourInForBritain pic.twitter.com/Ydp46ablsR— Maria Eagle MP (@meaglemp) February 20, 2016
The Associated Press contributed to this report.