Tory MP Louise Mensch has said she did class A drugs in her youth and that it had "long term mental health" effects on her.
Appearing on the BBC's Question Time programme on Thursday evening, the Tory MP for Corby repeated the admission she first made in November 2011.
"The plain fact of the matter is drugs are incredibly addictive and destroy lives," she said. "Given that scourge is there the question is what you do about it."
"I am somebody who has used drugs in the past, I have used class A drugs in the past, I said this when someone tried to blackmail me over this during the Murdoch hearings.
"It's something I regret incredibly, that in my youth I messed with my brain," she added.
Mensch was responding to a question about whether drugs should be legalised following comments by justice secretary Ken Clarke that Britain was "losing" the war on drugs.
"It has had long term mental health health effects on me, it has caused me to be more anxious than I need to be, it is not something we need to glorify."
Mensch said that legalisation and making drugs "more easily available to people" was "exactly the wrong way to go."
However pressed by presenter David Dimbleby as to what drugs she had taken, Mensch said she did not want to say.
"I have never said, I said they were class A," she said. "I don't want to say so because I don't want to glorify those drugs."
She added: "I did serious drugs and it messed with my head and it's a terrible thing."
In November 2011 Mensch admitted having taken class A drugs in her youth after a investigative journalists contacted her to confront her with specific allegations about one incident.
In an attempt to take the wind out of the story before it was published, Mensch said it was "highly probable" she had taken drugs at the time.
"I'm sure it was not the only incident of the kind; we all do idiotic things when young," she said.
She won plaudits from political friends and foes at the time for her candour.
Following her comments on Question Time Mensch once again won admirers, who praised her for feeling able to speak about her experiences on TV.Suggest a correction