Boris Johnson refuses to elaborate on previous drug use claims
Probing questions about previous misdemeanours and the use of drugs have become an evergreen feature of the Conservative Party leadership race.
But while candidates such as Michael Gove and Rory Stewart made revelatory comments about their historic dabblings in illegal substances - with cocaine and opium, respectively - Boris Johnson appeared to side-step the issue.
Asked to comment on his previous confession at having used cocaine during an interview with British GQ magazine in which he said it "achieved no pharmacological, psychotropical or any other effect on me whatsoever", Mr Johnson was reluctant to elaborate.
He said: "I think the account of this event when I was 19 has appeared many, many times.
"I think what most people in this country want us to really focus on in this campaign, if I may say so, is what we can do for them and what our plans are for this great country of ours."
Mr Johnson said he "cannot swear that I have always observed a top speed limit, in this country, of 70mph" when asked whether he had ever done anything illegal.
The former London mayor is the bookmakers' favourite to replace Theresa May, who infamously said the naughtiest thing she had ever done was "running through fields of wheat" as a child.
Former News Of The World editor and current Good Morning Britain host Piers Morgan, who elicited Mr Johnson's admission about cocaine use during the interview for GQ in 2007, responded in a tweet: "Boris admitted taking cocaine. Unequivocally. I know this because I'm the one he admitted it to.
"The interesting question is why such an admission is deemed campaign-wrecking for Gove but not for Boris..."