The last three polls on Scottish independence voting intention have put support for leaving the UK at between 49 per cent and 52 per cent, when the don’t knows are removed.

An online poll at the start of August conducted by Lord Ashcroft also put independence in the lead for the first time in two and a half years, while polling expert Professor Sir John Curtice has said that “it can no longer be presumed that Scotland would vote ‘no’ again in an independence ballot”.

A dossier of Scottish coverage of the Ashcroft opinion poll - conducted in the wake of Mr Johnson’s first visit as Prime Minister to Scotland - was sent to Number 10 by former Scottish Tory leader Ruth Davidson. It also saw almost half polled – 47 per cent – say they wanted a second independence referendum to be held within the next two years.

All Under One Banner Independence March - Holyrood to Meadows on Saturday. Picture: Lisa Ferguson

IndyRef2 support needed for labour to gain SNP backing, Ian Blackford says

Downing Street is too complacent about the danger of a second independence referendum a senior Whitehall official has said, with a lack of “panic” at the most senior levels about the strengthening trend in polling on Scottish independence.

However, when asked if there was panic in Downing Street at the shift in attitudes towards independence, the Whitehall source responded: “There isn’t nearly enough panic.”

They added: “The 55-45 result in 2014 was close enough.”

Concerns raised before Boris Johnson became Prime Minister that his Brexit policy would prove divisive within the UK nations, have been reflected in the most recent polling and in research by the Centre on Constitutional Change which showed the Brexit was “dislodging the long-held red lines about the [UK] union”.

It found that a majority of Conservative voters in England would prefer to press ahead with Brexit even if it led to Scottish independence and the collapse of the Northern Irish peace process.

Mr Johnson has also stuck with the hard line established at the start of this year by Mrs May, who said she would not grant permission for a second independence referendum if powers were requested by the Scottish Parliament. Last month the Prime Minister also told journalists at a reception in Downing Street that “it was a once in a generation vote”.

His “muscular unionism” has been reflected by a number of Scottish Tory MPs, including Andrew Bowie who last week was criticised for claiming the UK had “given away” Bute House and Edinburgh Castle to Scotland as part of the devolution settlement, branding it a “mistake.”

The MP for West Aberdeenshire and Kincardine, labelled the castle one of the “fantastic assets” of the United Kingdom but lamented the fact it can no longer be used for UK Government functions, however the Castle was previously part of the Crown Estate, and never “owned” by the UK government.

However one concession reportedly made by Downing Street to its ‘Union unit’ - led by a former Scottish Conservative Party aide - is an agreement with the Scottish Tories not to comment on what conditions would ‘trigger’ permission for a second independence referendum.

The internal Tory agreement came after the Labour Party row over the summer about its stance on the granting of a Section 30 Order, with the UK and Scottish parties at odds over the issue.

No coalition with Labour unless IndyRef is backed

SNP Westminster leader Ian Blackford yesterday put more pressure on Labour over the issue saying his party would only support a Jeremy Corbyn government, in the result of a hung Parliament, if a Section 30 Order was granted.

Ian Blackford told the BBC’s Sunday Politics Scotland programme that they would not form a coalition with Jeremy Corbyn’s party, but that they would be prepared to work with them on a “progressive basis”. The MP for Ross, Skye and Lochaber was asked if support for a minority government would depend on them being given a Section 30 Order - legislation which gives Holyrood the power to stage a referendum.

Asked if there were discussions about conditions of co-operation with Labour he replied that Mr Corbyn had to “respect democracy”. Mr Blackford added: “We have that mandate there. If the people in a Westminster election reinforce that by voting for the SNP, he has to respect that it should be the Scottish Parliament that determines when a referendum is called, not a government in Westminster.

“It is absolutely the case that everything that was seen going on at Westminster demonstrates that the people of Scotland have got to have the right to determine their own future - that means that we have to have that Section 30 sitting in the hands of the Scottish Parliament.”

Scottish Labour leader Richard Leonard said last month that the party would oppose a second referendum on independence in its next UK manifesto. It came after Mr Corbyn said he would “decide at the time” whether to approve a Section 30 order, and shadow Chancellor John McDonnell saying a Labour government would not stand in the way of a referendum if there was support for one in the Scottish Parliament.

Nicola Sturgeon is expected to request powers for a second referendum under Section 30 of the Scotland Act before the end of the year. She had previously said a referendum should be held in 2021, but recently shifted that date to 2020 and the Scottish Government is currently steering a Referendums Bill through the Scottish Parliament.

"They will not fool the Scottish people twice.”

The SNP will gather for their autumn conference next Sunday, with the First Minister under pressure from activists and several elected members to keep up the momentum towards a new vote on independence.

SNP MP Angus MacNeill, one of those who has called for a swift move to another referendum, said the UK Government would be unable to resist demands for a second independence poll indefinitely. “Indyref2 is coming and the Tories know this,” Mr MacNeill said. “They have shown the current UK Union to be a mess and they have made it worse.

“Just about every promise they made to the Scottish people in 2014 - like vote No to remain in the EU - was a lie. They are in a panic because they know they will not fool the Scottish people twice.”

Mr Blackford also hit out at the Prime Minister’s “bluff and bluster” over the Court of Session case yesterday and Boris Johnson’s claim that the UK would come out of the EU no matter what. He said if the government did not comply with the Benn Act, and ask for an extension there were “things we can do”.

“All the opposition parties, including the Tory rebels, have a majority so we can dictate the agenda and bring forward legislation,” he said. “We’ve gamed out all of this and know exactly how we can do this. The ultimate would be to bring down the government through a vote of no confidence.”

Mr Blackford said a General Election should be held before another EU referendum, as to ask an emergency government to “sit in office for a number of months and even pass a budget, that’s a tall order”. But he added: “I would say to everyone, we’ve come a long way, we’ve got the Benn Act in place but a Prime Minister in office we can’t trust. Let’s go the extra mile, whether its Jeremy Corbyn or anyone else, let’s put someone in office to send that letter.”

Jeremy Corbyn is set to meet with Mr Blackford and the leaders of other opposition parties in Westminster to scrutinise the Government’s new Brexit proposals today, with the cross-party meeting deciding on its next steps to “hold the Government to account”. Ahead of the meeting, Mr Corbyn said: “Labour is continuing to lead cross-party efforts to prevent a damaging No Deal.

Today’s meeting will give us the chance to scrutinise the Government’s proposals together.

“It’s already clear that Johnson’s proposal would slash food safety and standards, exposing us to - among other things - chlorine-washed chicken and hormone-treated beef, currently banned under EU standards.

“That’s what a Trump Deal Brexit would mean in practice.”

Time for some ‘panic’ over Scottish independence referendum says Whitehall official