The Conservative Party's vice-chair has admitted "hacking" into a Labour opponent's website.
Kemi Badenoch has apologised for the "foolish prank" she carried out more than a decade ago, on Labour MP Harriet Harman's website.
In an interview with Core Politics she was asked what the "naughtiest thing" she has ever done was.
She replied: "About 10 years ago I hacked into... a Labour MP's website and I changed all the stuff in there to say nice things about Tories."
She told the paper: "This was a foolish prank over a decade ago, for which I apologise."
Ms Harman tweeted, saying she had received a written apology from the Tory MP and accepted it.
She wrote: "@KemiBadenoch has written to me apologising. I have accepted her apology."
Hacking is a criminal offence, which can result in two years in prison and/or a fine under the Computer Misuse Act 1990.
Badenoch was appointed the Conservative Party's vice-chair for candidates in January.
Tory sources stressed Ms Badenoch was not a candidate or professionally connected to the party at the time of the hacking.
It is understood it involved guessing a password on the website.
Mustafa Al-Bassam, a computer science PhD researcher at University College London said he had reported the incident to cyber crime authorities at Action Fraud.
"I hope they do take this matter seriously, and apply the law equally to Tory MPs as they do to hacktivists who have gone to jail for less," he said.
Naomi Colvin, director of activist charity the Courage Foundation, said Ms Harman's acceptance of Ms Badenoch's apology "renders the likelihood of a prosecution unlikely".
She said: "This is an entirely appropriate way to deal with a trivial incident and highlights just how ridiculously heavy handed most prosecutions of online activists are."