Boris Johnson says country wants to focus on his plans for Britain and not his personality

Boris Johnson launches his campaign to become leader of the Conservative and Unionist Party and Prime Minister at the Sky Loft, Millbank Tower. Photograph: Stefan Rousseau/PA Wire. - Credit: PA

Boris Johnson has insisted his past comments and behaviours do not make him a poor choice for prime minister.

Probing questions about previous misdemeanours and the use of drugs have become an evergreen feature of the Conservative Party leadership race with candidates such as Michael Gove and Rory Stewart made revelatory comments about their historic dabblings in illegal substances – with cocaine and opium, respectively.

But 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”, 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.”

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.

When challenged by a reporter about past comments, including saying Muslim women wearing burkas “look like letter boxes”, Johnson said: “I want to make a general point about the way I do things and the language I use.

“Occasionally some plaster comes off the ceiling as a result of a phrase I may have used, or the way that phrase has been wrenched out of context by those who wish for reasons of their own to caricature.

“But I think it’s vital for us as politicians to remember that one of the reasons that the public feels alienated now from us all as a breed, is because too often they feel that we are muffling and veiling our language, not speaking as we find – covering everything up in bureaucratic platitudes, when what they want to hear is what we genuinely think.”

On his use of the term “fuck business”, he said he had spent a lot of time as foreign secretary promoting British business.

He added: “I don’t think there is anybody in the modern Conservative Party who can honestly be said to have done more to stick up for business, even in the toughest of times.”

As Johnson spoke, Labour MP David Lammy tweeted: “Boris Johnson says the UK must ‘have the guts’ to prepare for No-Deal Brexit. But he turns down countless debates, interviews and outright refuses to put it to the country in a #PeoplesVote. This is not leadership, it is shameless opportunism that will cause permanent damage.”

He added: “Boris Johnson says with a straight face he will ‘unite this country and unite this society’. The same man who described black people as ‘piccaninnies’, mocked Muslim women as ‘bank robbers’ and peddled lies throughout the referendum. Britain deserves so much better than this.”