The YouGov survey, carried by The Times, of 1,090 voters is the first time the firm has recorded a lead for “Yes” in more than two years and follows three other polls that have shown an increase in support for independence after the Supreme Court ruled that Holyrood lacked the powers to unilaterally call an independence referendum.

The YouGov poll follows three other polls from Redfield & Wilton Strategies, Ipsos and Find Out Now that all showed an increase in support for Scottish independence.

In the latest poll, 47 per cent would vote in favour of Scottish independence in another referendum, an increase of four points on the survey from the same organisation in October, with the YouGov poll showing support for the Union has dropped by three points to 42 per cent.

A four poll in a row has shown increased support for Scottish independence

When undecided and non-voters were excluded, support for independence was at 53 per cent with 47 per cent backing remaining in the Union.

51 per cent of those polled believed Scotland has the right to call the next independence referendum, despite the Supreme Court ruling, with 52 per cent opposed to another ballot in 2023, but 51 per cent believing there should be a referendum in the next five years.

Despite the boost for pro-independence parties there were mixed results on the prospect of a de facto referendum. The YouGov poll quizzed those partaking on their attitude towards plans to treat the next general election as a “de facto referendum”, with 52 per cent of those polled saying they did not think that pro-independence parties securing a majority of the vote constituted a mandate to break up the Union. 23 per cent of SNP supporters did also not agree that victory in a de facto referendum gave Scotland the right to seek independence. Thirty-nine per cent of people said such a result would be enough to leave the UK,

Under the SNP’s de facto referendum plan, if more than 50 per cent of the electorate voted for pro-independence parties then the Nicola Sturgeon would argue that she has a mandate to open secession negotiations with the Prime Minister. The UK government has repeatedly ruled out a repeat of the 2014 referendum.

Polling around the next general election showed support for the SNP decreasing by two points to 43 per cent. Backing for Labour also dropped two points, to 29 per cent with Conservative support increasing by two points to 14 per cent.

Professor Sir John Curtice, of Strathclyde University told The Times that said that this was the joint highest pro-independence result recorded by YouGov, equalling a level last seen in August 2020 and the early stages of the Covid-19 pandemic.

He said: "On this evidence, just saying 'no' to another ballot does not look like a viable long-term strategy for maintaining public support for the Union."

According to Curtice's analysis, the SNP would lose two MPs to return 46 members to the Commons.

Scottish independence: Support for independence grows in fourth consecutive poll