A former Welsh secretary has been cleared of breaking the ministerial code over claims he knew a former aide had collapsed a rape trial.
An inquiry found it “unlikely” Alun Cairns had not been made aware of Ross England’s role in the collapse.
The investigator said those involved said they did not inform Mr Cairns of Mr England’s role, and there was “no direct evidence to contradict this”.
Mr Cairns insisted he did not know the details of the case.
He resigned from the cabinet in November after the row broke out, just before the official start of the general election campaign.
The position of Welsh secretary remained vacant during the campaign, in which Mr Cairns successfully defended his Vale of Glamorgan seat.
However, Prime Minister Boris Johnson named Simon Hart as the new Welsh secretary following the Conservative victory.
In his resignation letter to the prime minister in November, Mr Cairns said: “I will co-operate in full with the investigation under the ministerial code which will now take place and I am confident I will be cleared of any breach or wrong-doing.”
In April 2018, as a witness at the rape trial of his friend James Hackett, Mr England told Cardiff Crown Court he had a casual sexual relationship with the complainant – which she denied – despite the judge making it clear that evidence of the sexual history of the victim was inadmissible.
Judge Stephen John Hopkins QC said to him: “Why did you say that? Are you completely stupid?
“You have managed single-handed, and I have no doubt it was deliberate on your part, to sabotage this trial… get out of my court.”
Hackett was subsequently convicted of rape at a retrial.
Mr England was chosen in December 2018 as the Vale of Glamorgan candidate for the 2021 Welsh assembly election.
At the time of his selection, Mr Cairns endorsed Mr England as a “friend and colleague” with whom “it will be a pleasure to campaign”.
In October this year, BBC Wales discovered an email sent on 2 August 2018 to Mr Cairns by Geraint Evans, his special adviser. It was also copied to Richard Minshull – the director of the Welsh Conservatives – and another member of staff.
It said: “I have spoken to Ross and he is confident no action will be taken by the court.”
When the story came to light, Welsh Conservative party chairman Lord Davies of Gower said he could “categorically state” he and Mr Cairns were “completely unaware of the details of the collapse of this trial until they became public”.
Mr England was suspended as a candidate and as an employee after details of the court case emerged, with the party saying a full investigation would be conducted.
The rape victim previously said Mr England’s selection “shows how little respect they have for me” and she called for Mr Cairns to quit.
A UK Government Cabinet Office investigation was launched following Mr Cairns’ resignation from Boris Johnson’s cabinet in November.
Sir Alex Allan, the prime minister’s independent adviser on ministerial standards, has concluded that the evidence does not uphold the allegations against Mr Cairns.
In his report, Sir Alex said: “I find it unlikely that Mr Cairns would not have been told something about Mr England’s role when he was told about the collapse.
“But all those involved state that they had not informed Mr Cairns of Mr England’s role, and there is no direct evidence to contradict this.
“On that basis, I do not find that the evidence upholds the allegations of a breach of the Ministerial Code.”
The rape victim told BBC Wales that she was “disappointed but not surprised” by the investigation’s conclusion.