A BREXIT could lead to the “disintegration” of the UK, David Cameron has warned, despite the Scottish Tory leader Ruth Davidson insisting that a vote to pull out of the EU would not trigger a fresh independence referendum.

Nicola Sturgeon has said there will be an "almost certain” drive for another independence referendum north of the Border if Scotland votes to stay in the EU but England votes to leave on June 23.

By contrast, Davidson said that even Britain leaving the EU against the wishes of a majority of Scots would not mean another referendum, as she stated such a vote was “off the table for five years” due to the SNP’s failure to seek an electoral mandate for one.

However, the Prime Minister appeared to contradict his party's leader in Scotland, using a speech in London to note that the UK was in a voluntary union of four nations and urging voters to go to the ballot box with their “eyes open”.

During a speech at the British Museum setting out the case for Britain remaining part of the bloc, Cameron warned that Brexit could fuel a fresh push for Scottish independence.

He said: “Let me just say this about Scotland – you don’t renew your country by taking a decision that could ultimately lead to its disintegration. So, as we weigh up this decision, let us do so with our eyes open.”

Cameron’s remarks came as pro-EU campaigners in Scotland warned the European referendum must not be “a contest of two different kinds of right-wing, conservative politics” following a clash between the Prime Minister and Boris Johnson over whether a Brexit would put peace in the continent at risk.

Cameron said the 28-nation bloc had reconciled warring nations and was playing a crucial role in the fight against Daesh and dealing with a “newly belligerent” Russia.

Former London mayor Johnson said defence alliance Nato had been the protector of Europe’s peace since the Second World War, and that the EU by contrast was “a force for instability and alienation”.

However, Alex Salmond and the Scottish Greens called for pro-EU campaigners to make a progressive case against a Brexit.

Scottish Green Europe spokesman Ross Greer, who was elected as youngest MSP at the age of 21, said the campaign in the run-up to the EU referendum should not be dominated be opposing factions of the Conservative Party.

Greer, one of six Green MSPs elected last week, said: “The referendum cannot be a contest of two different kinds of right-wing, conservative politics.

“Peace has been an under-appreciated success of Europe but we cannot lose sight of the fact that the Tories, whether under David Cameron or Boris Johnson, are in favour of more military muscle and arms deals with oppressive regimes.

“The Green case for Scotland and the rest of the UK remaining in the EU is one which furthers efforts to bring about peaceful solutions to the world’s conflicts."

Meanwhile, in a speech in Brussels yesterday former First Minister Salmond called on voters to ignore “projects fear” on both sides of the referendum debate, and instead focus on the positives of remaining part of the EU.

Salmond, who is the SNP’s foreign affairs spokesman in the Commons, said a key plank of the pro-EU case should focus on areas such as showing “solidarity and humanity” to people caught up in the refugee crisis.

He said: “Europe must lead – the way it lifted itself 66 years ago and resolved to work together – to build a universal right and hope for every EU citizen so we can live in peace and harmony.”