David Cameron has said the referendum on the UK's membership of the EU will take place on June 23.

The Prime Minister said leaving the European Union would be a "leap in the dark" as he urged voters to back his reform deal.

He said earlier that the deal, agreed between leaders of the 28 member-states at a meeting in Brussels, gave the UK "special status".

The Cabinet backed his plan but individual ministers have been allowed to campaign on either side.

Following his return overnight from the marathon EU negotiating session, the Prime Minister said that leaving would threaten Britain's "economic and national security".

Speaking at Downing Street, he said: "Those who want to leave Europe cannot tell you if British businesses would be able to access Europe's free trade single market, or if working people's jobs are safe, or how much prices would rise. All they're offering is a risk at a time of uncertainty - a leap in the dark."

Among the first UK ministers to declare they would be campaigning for an "in" vote were home secretary Theresa May, business Secretary Sajid Javid, international development secretary Justine Greening and transport secretary Patrick McLoughlin.

Minutes after David Cameron announced the date for the referendum a group of six Conservative MPs including Michael Gove and Chris Grayling appeared at the headquarters for exit campaign group, Vote Leave.

In a lengthy statement setting out his position, Mr Gove said the EU had "proved a failure on so many fronts" and that he had felt compelled to put his political convictions before his loyalty to the PM.

First Minister Nicola Sturgeon reiterated that she was opposed to a referendum on June 23, but said she would "get on with the job" of campaigning for a Remain vote.

She said: "We will make a strong, positive case for the many benefits EU membership brings in terms of jobs, investment, social and employment protections and collective security.

"The EU is a coming together of independent states that choose to pool some of their sovereignty to better tackle those issues that don't respect national boundaries, like climate change, energy security and the refugee crisis.

"It's not a perfect institution and while I believe it would be best for Scotland to be in the EU as an independent member state, I believe it is better for us in all circumstances to stay in."

She continued: "We made it clear to the Prime Minister that we were opposed to a June 23 referendum, given the overlap with our own Scottish election, but now that that date has been named we will get on with the job of campaigning for an ‘in’ vote."

Labour leader Jeremy Corbyn said the Prime Minister's negotiation of a new deal had been a "sideshow".

He said: "[The Prime Minister's] priorities in these negotiations have been to appease his opponents in the Conservative Party. He has done nothing to promote secure jobs, protect our steel industry, or stop the spread of low pay and the undercutting of wages in Britain. Labour’s priorities for reform in the EU would be different, and David Cameron’s deal is a missed opportunity to make the real changes we need.

"We will be campaigning to keep Britain in Europe in the coming referendum, regardless of David Cameron’s tinkering, because it brings investment, jobs and protection for British workers and consumers. Labour believes the EU is a vital framework for European trade and cooperation in the 21st century, and that a vote to remain in Europe is in the best interests of our people."

Scottish Conservative leader Ruth Davidson welcomed the announcement of the referendum, pointing out that anyone under the age of 58 has never had a vote on the UK's European membership.

She said: "For my own part, I believe that - on balance - Scotland's businesses do better from being part of the biggest free trade bloc in the world, and I hope the country chooses to remain."

The Scottish Greens said the date of the referendum is "disrespectful to voters" in Scotland and the other devolved areas that are also holding elections on May 5.

Ross Greer, Europe spokesman for the Scottish Greens, said: "Holding the referendum just weeks after major elections across the UK makes it harder to have the substantial debate we need on the UK's future within Europe.

"David Cameron has once again shown he has no regard for voters in Scotland, Wales and Northern Ireland."

Scotland Stronger In Europe - the Scottish arm of Britain Stronger In Europe - erected a street stall in Glasgow's Sauchiehall Street to promote the UK's continuing membership of the EU.

Campaign spokesman John Edward said: "Scottish votes could be crucial in keeping the UK in Europe, so it is important that Scotland comes together and chooses a future in Europe.

"There is strong support in Scotland to stay in the EU, and we want to motivate people with positive campaigning to turn out and vote for 'Remain' on June 23."