The former first minister of Scotland Alex Salmond is facing a political backlash after agreeing to host a talk show on RT, the Russian state-owned broadcaster.

Nicola Sturgeon, Salmond’s successor and leader of the SNP, has questioned his decision to work with RT in comments that represent a rare and significant rebuke for her former colleague.

Sturgeon said that Salmond’s choice of channel “would not have been my choice” and revealed she had not been informed of the move prior to its announcement.

“I am sure Alex’s show will make interesting viewing – however, his choice of channel would not have been my choice,” she said.

“Of course, Alex is not currently an elected politician and is free to do as he wishes – but had I been asked, I would have advised against RT and suggested he seek a different channel to air what I am sure will be an entertaining show.

“Neither myself nor the SNP will shy away from criticising Russian policy when we believe it is merited.”

RT has been criticised as a propaganda tool for Putin’s government, a claim that has been mocked by the channel through a series of adverts.

The Alex Salmond Show will involve current affairs discussions and interviews with guests, covering politics, showbiz and sport. It will start next Thursday and will air weekly.

Salmond was immediately criticised when the show was announced on Thursday, with Willie Rennie, the leader of the Scottish Liberal Democrats describing it as “unedifying spectacle”.

Salmond has defended the show by stating that it will be made by his own production company Slainte Media, which he set up with former SNP MP Tasmina Ahmed-Sheikh, and that dozens of Conservative, Labour and SNP MPs have appeared on RT in the last couple of years.

But Jackson Carlaw, the deputy leader of the Scottish Conservatives, said it “beggars belief” that Salmond would work with RT.

“It’s clear that Alex Salmond’s moral compass now points towards Vladimir Putin’s corrupt regime in the Kremlin,” he said. “It beggars belief that a man who led Scotland for seven years should be reduced to a puppet of Russia’s deeply damaging propaganda unit.

“Along with most people, ordinary SNP activists will be appalled by Mr Salmond’s actions.”

Anas Sarwar, a candidate to lead Labour in Scotland, said Salmond had demonstrated an “astonishing lack of judgment”.

However, it is Sturgeon’s comments that represent the most significant intervention about Salmond’s announcement. She is frequently called upon to clarify Salmond’s increasingly optimistic predictions about the proximity of another independence referendum.

Sturgeon’s summer recess was interrupted when she was forced to defend Salmond against charges of sexism at his Edinburgh Fringe show, following a crude joke about women politicians. Sturgeon conceded: “Occasionally, Alex is not as funny as he thinks he is.”

But her close relationship with her friend and mentor appears to have endured Salmond’s congenital headline-grabbbing, and, in a highly personal interview given before the SNP’s conference in October, she described his departure from Westminster as “like losing a limb”. She also insisted that Salmond remained the first person she turned to for political guidance.

Salmond himself has a fraught relationship with the media, forged during the Scottish independence campaign of 2014.

When pro-independence demonstrators gathered outside the BBC to protest against the perceived bias of then political editor Nick Robinson, Salmond described the crowd as “peaceful and joyous”, despite the fact that there was at least one effigy of the journalist in evidence.

Sturgeon at the time distanced herself, suggesting that protesters would be better employed spending the final days “not protesting against something but campaigning for something”.

Salmond has continued to attack BBC coverage, and also banned several anti-independence papers from his resignation press conference at Bute House.

He is now bidding to become chair of the Scotsman’s parent company, Johnston Press, with the stated intention of making the newspaper “more pro-Scottish”. This prompted the newspaper’s editor, Frank O’Donnell, to hit back in a full-page editorial, pledging to protect the paper’s editorial independence and describing him as ignorant and “equating pro-Scottish as being pro-SNP”.