Justice Secretary Keith Brown has insisted that he had no knowledge of a transgender prisoner temporarily being held in a female jail – as he admitted there will be “exceptional circumstances” where plans will need to be signed off by SNP ministers.

The minister addressed MSPs in Holyrood after the Scottish Government has faced criticism for a U-turn over trans prisoners.

The Scottish Government announced on Sunday that there will be a temporary blanket ban on transgender people with a history of violence against women being placed in a female prison or those inmates will be moved out of a female prison if they are currently placed there.

The First Minister has suggested that the temporary ban could become permanent, telling broadcasters that “pending a wider review”, the change would “make it absolutely clear that no transgender prisoner with a history of violence against women will be placed in the female estate”.

Read more: Nicola Sturgeon urged to clear up trans prisoners 'chaos'

Mr Brown was forced into the U-turn on Sunday following a public backlash after transgender rapist Isla Bryson was being held in isolation at a female prison for attacking two women when she was a man. She has now been moved to a male prison.

It then emerged that another violent trans criminal – Tiffany Scott – had applied to be moved from a male to a female prison.

Mr Brown told MSPs he was “very conscious of the importance of maintaining public confidence in the justice system”, following the situation, as he called for discussions to be “calm and founded on facts”.

He said: “We must not allow the legitimate questions that have been asked to fuel the view that trans women suddenly pose an inherent threat to women when that is not the case.

“What is important is the crime that they have committed and the risks that they pose to other prisoners, to staff and indeed themselves.”

Read more: Brown halts violent transgender prisoners moving to female jails

Mr Brown told Holyrood that “around 17 trans women” are currently in prisons in Scotland, “the majority of whom are kept in the male estate”.

He stressed that “no transgender prisoner will be placed in the general population either male or female, without risk assessment”.

Pointing to the case involving Ms Bryson, Mr Brown said: “During the period of risk assessment of the prisoner convicted of rape that had been admitted to HMP Cornville the individual was segregated from the rest of the prison community.

“This was done in accordance with the prison services established policy and practice.

“While the assessment was in progress, the decision was taken by the SPS that the individual should be transferred to the male estate.

“The SPS was of course aware of ministers’ views, it would be frankly bizarre if they were not aware of ministers’ views, but it remains an operational decision for the SPS based on the information available to it.”

Read more: Ministers may consider separate trans prisoners unit after rapist row

Mr Brown stressed that “the decision to initially accommodate this prisoner at HMP Cornville for the risk assessment was done was made without ministerial involvement”.

The minister told MSPs there would still be “exceptional circumstances” where SNP ministers would formally intervene.

He said: “It's felt that following through with robust risk assessment and taking account of all relevant factors, there are still exceptional circumstances in particular cases that will require the approval of ministers.

“This is not dissimilar to the situation which was announced last week in England or Wales.

“The prison service will seek ministerial approval for these particular cases which will not change the general position that decisions on the management and accommodation of prisoners within the prison estate have been and will continue to be operational matters for the Scottish Prison Service.”

Conservative community safety spokesperson, Russell Findlay, who has put pressure on the Scottish Government over the situation, called for evidence to be published that no ministers or government officials knew Ms Bryston was being held in a male prison.

He said: “ Now that Keith Brown tells us today that ministers had no awareness of the rapist moved to Corton Vale, will he explicitly state that none of his officials had prior knowledge?

“And will he published a detailed timeline of these critical events, including all correspondence?”

Mr Brown confirmed he was “happy to look at the requests” from Mr Findlay, adding that “as far as it's possible, I'm happy to provide the information”.

Mr Findlay said: “It was only six days ago that I asked Keith Brown about a double rapist in a women’s prison and he stood there and passed the buck.

“Less than 24 hours later, Nicola Sturgeon was forced into a humiliating U-turn and the rapist was rightly removed.

“Keith Brown now says that ministers had no awareness of the rapist being sent to Cornton Vale, but he was unable to definitively say that none of his officials had prior knowledge.

“We need a detailed timeline of these critical events, including all correspondence, that led to the disgraceful decision being reached and then over-turned. It’s clear there are still unanswered questions on this issue.

“SNP ministers are all over the place on this – because their position keeps unravelling with each fresh U-turn.

“Keith Brown insisted he still supports the principle of gender self-ID, yet the double rapist case has shown it is a disaster in practice. He needs to ditch the policy for good.”

In a letter to Holyrod's Justice Committee, Mr Brown said politicians "must not allow any suggestion to take root that trans women pose an inherent threat to women".

He added: "Predatory men are the risk to women. However, as with any group in society, a small number of trans women will offend and be sent to prison."