Alun Cairns has resigned as Secretary of State for Wales after being accused of lying about his knowledge of an allegation that a Tory candidate had sabotaged a rape trial.
In his resignation letter to the Prime Minister, Mr Cairns wrote, "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."
He is not standing down as a candidate in the upcoming general election.
The Prime Minister responded to Mr Cairns' letter saying he is "pleased" he will be cooperating fully with the Cabinet Office during the process.
Mr Johnson thanked him for his "support" he has given to the Government in "ensuring we honour the commitment to the people that we leave the European Union".
According to an investigation by BBC Wales, Mr Cairns was told about events in court in an email sent before Ross England was chosen as a candidate for the 2021 Welsh Assembly election.
England was praised by his former boss, Alun Cairns, in a press release welcoming his selection, and described the pair as “friends and colleagues”.
Mr England was a witness at the trial of James Hackett, 31, from Kingston upon Thames, for rape in April last year.
Barristers for both the prosecution and defence had agreed there could be no mention of the sexual history of the victim, then aged 21.
Within minutes of taking his oath at the trial in April Mr England told the jury he had previously had a relationship with the victim.
In front of the jury Judge Hopkins asked Mr England why he made the comments about past relations with the victim. "Why did you say that? Are you completely stupid?" he said. Mr England responded: "I apologise."
In response Mr England said: "I was not told that anything had been ruled inadmissible prior to my testimony. I gave an honest answer, honouring the oath I took to tell the truth, the whole truth, and nothing but the truth."
Following his resignation from government, Welsh Conservatives leader Paul Davies said, “I am sorry to see Alun resign today as the Secretary of State for Wales however, under the circumstances this was the right decision for him. Alun has rightly stated that he will cooperate fully with any investigations.
“I would like to thank Alun for his service to Wales as our Secretary of State where he brought an end to the Severn Bridge Tolls which will leave a lasting legacy on the Welsh economy.”
Labour are calling for Mr Cairns to also stand down as a candidate describing his decision on Wednesday to resign from Government as a "shoddy halfway house".
“Alun Cairns stepping down as Secretary of State is far from the end of the matter, and is a shoddy halfway house that will fool nobody.", Christina Rees said in a statement.
“He has still not explained his behaviour and still not addressed the grave issues raised by the leaked emails yesterday. Worse still, neither he nor any senior Welsh Tory have apologised to one person who most deserves it - the victim herself.
“He should do the right thing - apologise, and step down as a candidate.”
Plaid Cymru’s Liz Saville Roberts said Mr Cairns "conduct proved unquestionably that he is not fit to hold ministerial office."
“I hope that Alun Cairns’ resignation as Secretary of State proves to be some solace to the woman at the centre of this case, who still has received no apology from the Conservative party."
Leader of the Welsh Liberal Democrats Jane Dodds echoed those calls and said it is "clear he is not fit to represent Wales."
“These recent events show he is not fit to represent the Vale of Glamorgan in Westminster either.
“There must now be a full independent investigation to determine what people knew, when they knew it and how Mr England was able to be selected as a candidate despite his actions."