Swinney reveals reservations about Sturgeon’s post-Brexit indyref strategy

His frank discussion of the party’s direction is contained in a new documentary airing on the BBC on Tuesday, which chronicles the political alliance forged between Ms Sturgeon and Alex Salmond.

Salmond and Sturgeon: A Troubled Union features insights from figures at the top of the SNP and Scottish politics over the last four decades.

It examines their tenure in the party during its rise to become the dominant political force north of the border – and ultimately how they became irreconcilably split.

One part of the documentary focuses on the aftermath of the 2016 Brexit vote.

At the time Mr Swinney was deputy first minister, with Nicola Sturgeon leading the party.

After deliberating with her closest team, she wrote a speech in which she said a second independence referendum was now “on the table” as a result of the UK being about to leave the EU despite Scotland backing Remain.

Mr Swinney told the documentary: “I can remember saying to Nicola as she was formulating the message she was going to convey in the aftermath of the Brexit referendum – was she sure that she wanted to say so firmly that she was opening up dialogue about a further referendum.”

He continued: “I have to say I was nervous, because I was still concerned by how we were able to motivate people in Scotland when we had just had one (a referendum) in 2014.”

Mr Swinney also discussed Mr Salmond’s condemnation of the Nato military intervention in Kosovo in 1999.

He said the language Mr Salmond used was “not appropriate, not correct”.

The documentary also features extensive interviews with Ms Sturgeon and Mr Salmond themselves.

The former MP for Banff and Buchan, who now leads the rival Alba Party, said he believes he was “right back then” on Kosovo but conceded it was not a “convenient” thing to say ahead of the first Scottish Parliament elections.

Scottish Labour ended up becoming the largest party in first session of the devolved parliament.

Mr Salmond said Ms Sturgeon’s post-Brexit strategy had led the independence movement “up the hill and then marched down again” – saying it had failed to deliver a second independence referendum.

In another part of the episode Mr Salmond says the combination of Nicola Sturgeon as SNP leader and her husband Peter Murrell as party chief executive would cause “great difficulty” for the party.

He said the press would “exploit” such a relationship when things went badly for the SNP and he had expressed his concerns to the couple.

Mr Salmond also spoke of his contempt at the team around Nicola Sturgeon when she became First Minister, saying he didn’t “rate them highly”.

In her own interview, Ms Sturgeon reflected on how Mr Salmond had been “integral” to some of the best moments in her life, making the breakdown in their relationship all the more difficult.

She had long been seen as his protege but their relationship soured in later years.

The former first minister described how her political activism in the 80s and 90s helped her overcome shyness. She quickly became one of the SNP’s strongest communicators.

Discussing the post-Brexit period, she said there was a lot of debate in her core team about the best way forward – saying Mr Salmond was initially “gung ho” for another independence referendum before going in the other direction.

Mr Sturgeon said her relationship with her former mentor changed suddenly in the wake of the 2017 general election, when Mr Salmond lost his seat at Westminster.

She said: “He didn’t take my call for two weeks afterwards …

“Suddenly I felt he was very deliberately rejecting me and punishing me for whatever he thought I had got wrong.”

The first episode of A Troubled Union will be broadcast on BBC Scotland at 10pm on Tuesday.

The second episode will be broadcast at the same time on Wednesday.

It will feature the criminal case against Mr Salmond, where he was cleared of sexual assault, and his legal battle with the Scottish Government.