A vote to leave the EU against Scotland's will would "almost certainly" trigger another independence referendum, Nicola Sturgeon has said.

Ms Sturgeon said there would be an "inescapable" shift in public opinion towards independence to guarantee Scotland's continued EU membership.

And it is "inevitable" that people who voted No in 2014 would change their minds, she added. She also warned leaving the EU would see the Conservative government "unfettered" to water down UK employment rights and social protections.

On Saturday David Cameron announced the referendum would be held on June 23. He said the new deal he had negotiated gave the UK "special status" within the EU.

Ms Sturgeon was asked if a vote to leave the EU against the majority will of the people of Scotland would definitely trigger another independence referendum on the BBC's Andrew Marr Show on Sunday.

She replied: "Almost certainly. I think that would be the demand of people in Scotland.

"Let me say very clearly that I don't want this scenario to arise. I hope the UK as a whole votes to stay in the EU for a whole variety of different reasons.

"But if you cast your mind back to the Scottish referendum, the No campaign then said if Scotland voted Yes then our membership of the EU would be at risk. That was rubbish then, but that was a key argument.

"If, a couple of years later, we find ourselves, having voted to stay in the EU, being taken out against our will, I think there will be many people, including people who voted No in 2014, who would say the only way to guarantee our EU membership is to be independent.

"That, I think, is inescapable."

She added: "I personally know people who were passionate in their No vote in 2014 who would change their minds if we were in that scenario.

"That, I think, is just something that is inevitable."

Ms Sturgeon acknowledged that an independent Scotland in the EU would have to negotiate its border arrangements if the remainder of the UK was outside the EU.

She added that said she has "no proposals" to use her new devolved powers to top up benefits for migrants, but said EU migrants have had a positive impact on the UK economy.

She also spoke of her fears for employment rights and social protections under the Tories if the UK leaves the EU.

She said: "David Cameron seems to want an EU where the social and employment protections that it brings are watered down.

"For me these are parts of the reasons for being in the EU, and one of the reasons why it would worry me greatly if the UK was to come out of the EU, as we would then have David Cameron's majority Conservative government unfettered when it came to employment rights or social protections."

She said Mr Cameron should "think twice" about coming to Scotland to make his case for remaining in the EU.

"In the independence referendum we used to be overjoyed when he made a foray into Scotland to campaign there, because we thought it ratcheted up votes for the Yes campaign," the First Minister said.

The First Minister’s comments were made on the same day London mayor Boris Johnson declared he would join the campaign for Britain to leave the European Union.

Making his announcement, Mr Johnson said David Cameron's re-negotiation had failed to deliver fundamental change in Britain's relationship with Brussels.

Responding to Ms Sturgeon's comments, Scottish Conservative chief whip John Lamont said: "As always with the SNP, everything comes back to their campaign for independence.

"Nicola Sturgeon said before the last referendum that it would be 'once in a generation'. Now, a year on a half on, she is already manoeuvring for a re-run.

"Scottish Conservative MSPs will proudly stand behind Scotland's decision to stay part of the UK, and we demand that the SNP does, too."

Scottish Liberal Democrat leader Willie Rennie said: "It is no surprise that Nicola Sturgeon favours independence for Scotland, but she is too keen to talk up a defeat in the EU referendum to advance her cause.

"It is welcome that Nicola Sturgeon supports remaining in the EU, but we need her to support the campaign 100% rather than using every opportunity to talk abut what happens if we lose.

"The EU referendum campaign must not be used as a proxy campaign for independence. The EU debate deserves a laser-like focus, just like the independence debate.

"With economic, social and security benefits, the European Union is good for the UK."