SUPPORT for Scottish independence will “exponentially rise” if Boris Johnson continues to "bunker down" and dismiss requests for a second referendum, the former Speaker of the House of Commons has said.

John Bercow suggested the UK Government would be unable to resist a second vote if there is evidence a majority of Scots want it.

He also said it is “perfectly possible” that Scotland may decide to hold a ballot without the consent of Westminster, and argued circumstances have changed since 2014.

Mr Bercow made the comments at an event in Edinburgh organised by the Topping & Company bookshop.

He said: “I think it will be quite interesting to see whether over a sustained period – let’s say two or three years – there is evidence of a majority of people in Scotland definitely wanting that further referendum, and/or definitely wanting Scottish independence.

“If that happens, it just seems to me that although legally a government might be able to resist, sometimes legal facts can clash with political reality.

“My view, by the way, for what it’s worth on Scottish independence is simply that ultimately, if you believe in sovereignty, if you believe in self-government, if you believe in the right of people to choose their own destiny, it has to be for the people of Scotland ultimately to decide. At the point at which they do, I think that decision has to be respected.”

Mr Bercow, who served as Speaker from 2009 until last year, said there are “very real” fissures between Scotland and Westminster.

He said there is an irony that “an avowedly, explicitly, robustly unionist Government, made up of the Conservative and Unionist Party, is in charge at a time when the strength of the UK has looked more precarious than for a long time, and the danger of it being ripped asunder [is] greater than for a long time”.

Mr Johnson formally rejected Nicola Sturgeon’s request for a second referendum last month.

The Prime Minister said Ms Sturgeon had previously pledged the 2014 vote was a "once in a generation" opportunity.

Mr Bercow argued the UK Government was legally within its rights to do this.

He said: “The Prime Minister is perfectly entitled to say ad nauseam to Ian Blackford and his SNP colleagues and Nicola Sturgeon, ‘Look you had your referendum on independence in 2014, we agreed it was once in a generation, you lost, we won, be quiet.’

“Legally, he’s entitled to say that. However, there’s one very important caveat.

“I’ve never championed Scottish independence and I’m not here to do that. Nor am I here to argue against it – I’m not here for that purpose at all.

“What I would say is this: it's important to be fair about this.

“At the time it was agreed it would be once in a generation, subject to one very important caveat – unless there was a material change.

“Ladies and gentlemen, it’s very hard to argue that there hasn’t been a change.”

He said the UK Government had asked Scots in 2014 to stay in the UK and remain part of the EU, "and that's no longer to be the case".

The former Tory MP said it is "absolutely predictable that support in Scotland for Scottish independence, and certainly for Indyref2, will exponentially rise" if Mr Johnson decides to "bunker down and just repeat that line over and over again".

He said managing the situation will require “diplomacy, nuance, subtlety and statecraft”, rather than “tub-thumping”, aggressive briefings from advisers or “clever, clever rhetorical tricks”.

Asked if there was any way Scotland could become independent without a referendum, Mr Bercow said: “It is perfectly possible at some stage – I’m not saying it will happen – but it’s perfectly possible at some stage that if people in Scotland feel that they are being arbitrarily and unreasonably prevented from having a referendum that they obviously want, they might decide to hold a ballot of their own even if it’s not authorised by Westminster.”

He said this would not be legally conclusive, “but politically it would be very significant – very significant indeed”.

“It would change the facts on the ground,” he added. “I’m not arguing for that, but I think that’s not out of the bounds of possibility.”

Mr Bercow frequently clashed with the Tory Government during his time as Speaker and faced accusations of bias in relation to Brexit.

He has also been accused of bullying parliamentary staff members, but strongly refutes this.

The former MP was speaking to an audience of around 450 people in Edinburgh to promote his new book, Unspeakable.