Image caption At the time of Ross England's (R) selection to stand as an AM, Alun Cairns (L) endorsed him as a "friend and colleague"

A UK cabinet minister has resigned over claims he knew about a former aide's role in the "sabotage" of a rape trial.

Welsh Secretary Alun Cairns denied knowing a Tory Welsh assembly candidate had made claims about a woman's sexual history in a rape trial in April 2018, causing the case to collapse.

BBC Wales found he was sent an email about the case over a year ago - he said he only heard about it last week.

Mr Cairns, who intends to stand again for Parliament, denies any wrongdoing.

His former aide, Ross England, was chosen as the Vale of Glamorgan candidate for the 2021 Welsh assembly election in December 2018 - four months after the email about him was sent to Mr Cairns.

At the time of his selection to stand as an AM, Mr Cairns endorsed Mr England as a "friend and colleague" with whom "it will be a pleasure to campaign".

Media playback is unsupported on your device Media caption Alun Cairns resigned the same day the Conservatives' election campaign began

Mr Cairns, who represented the Vale of Glamorgan, became one of the longest-serving ministers in the cabinet and worked under three prime ministers after being appointed in 2016.

In his letter to Prime Minister Boris Johnson, Mr Cairns said: "You will be aware of allegations relating to the actions of a party employee and candidate for the Welsh assembly elections in the Vale of Glamorgan.

"This is a very sensitive matter, and in light of continued speculation, I write to tender my resignation as secretary of state for Wales.

"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 his response, Mr Johnson said he was "extremely grateful for all the work you have done in the role as secretary of state since March 2016".

He added: "In particular, I would like to put on record my gratitude for all the support you have given to this government in ensuring we honour the commitment to the people that we leave the European Union.

"Given your long service as secretary of state, you can be proud of your record of delivery for the people of Wales, in particular in ensuring the abolition of tolls on the Severn bridges."

Mr Cairns intends to contest the Vale of Glamorgan seat in the 12 December general election.

But a Welsh Conservatives source questioned whether he should, saying: "If you can't hold the line as a cabinet minister, how could you credibly be a candidate."

At the 2017 general election, Mr Cairns won the seat by 2,190 votes over Labour.

Mr England said he had given an "honest answer" while giving evidence at the rape trial of his friend James Hackett.

He told the 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.

Months later, on 2 August 2018, an email was sent 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."

Last week, Tory 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 this week".

Mr England was suspended as a candidate and as an employee last week after details of the court case emerged and the party said a "full investigation will be conducted".

'I would like an apology'

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.

"If he'd come out and condemned Ross [England] in the first instance, he wouldn't be in this position," she said.

"I would like an apology from the party and Alun Cairns for selecting him in the first place. I can't believe that not one senior Welsh Conservative has said that what he did was wrong."

Image caption Ross England gave a speech at the Welsh Conservatives' conference in 2016

She added: "It is completely shocking to me that Ross England would stand up in court and say these things given that they are untrue.

"He was asked if we worked together, and the answer to that is yes.

"Nobody asked him if we were in a sexual relationship or not. For him to just blurt that out proves to me that it was a formulated plan that he and whoever else conjured to try and derail the trial.

"I think it was an absolutely deliberate attempt to sabotage the trial."

Lord Davies said the party only became aware of the "full extent of the proceedings" when Hackett's appeal process ended in October.

In a statement, Mr England said: "I gave an honest answer, honouring the oath I took to tell the truth, the whole truth and nothing but the truth.

"I complied fully with the conditions of the court before and after the trial."

What has the reaction been?

Stephen Crabb, Mr Cairns' predecessor as secretary of state for Wales, criticised his own party for being "too slow" in dealing with the matter.

"At the heart of this is a victim, a human being," he said. "A growing concern among candidates is that there were some serious and distressing statements being made by the victim and the party was too slow to show respect and provide full and dignified responses.

"The normal default rule for politicians, when difficult stories come along, is to keep your head down and pray it goes away. But for the kind of crime we are talking about here, that kind of posture doesn't work at all."

He added: "There's a wider issue here - we've never had a female Welsh Conservative Member of Parliament. There is a lack of women in senior positions in the Welsh Conservative Party.

"I'm not saying that would have fixed an issue like this, but when something like this comes along it's an opportunity for us as a party to ask, 'are we handling things correctly? Are our processes fit for purpose when something like this happens?' which as I say is very serious and deals with very sensitive matters."

Labour leader Jeremy Corbyn has questioned the "moral right" of Mr Cairns to stand as a candidate in the election.

Speaking on a visit in Crewe, he said: "He can legally stand, but does he have a moral right to stand as candidate? If he's stepping down as a minister because of his involvement, I would have thought the very least the Conservative Party can do is not put him up as a candidate in the next election."

Plaid Cymru candidate Liz Saville Roberts said Mr Cairns' conduct "is neither befitting of a government minister, nor of a Member of Parliament. Mr Cairns should do the honourable thing and withdraw from the election - and if he doesn't, the Conservative party should insist he withdraws".

Wales' Labour First Minister Mark Drakeford said: "The trial should never have been sabotaged - Ross England should never have been selected as a candidate, Alun Cairns should never have tried to cover up what he knew. When will the Tories finally do the right thing?"

Russell Spencer-Downe, deputy chairman of Vale of Glamorgan Conservatives Association, said he had faith in Mr Cairns, who had been "a very good MP and has always had the support of the association".

In addition to Mr Cairns, the following candidates are also standing in Vale of Glamorgan:

Sally Stephenson - Welsh Liberal Democrats

Belinda Loveluck-Edwards - Welsh Labour

Ian Johnson - Plaid Cymru

The close of nominations is 14 November.