Why it was pointless for Mumsnet to ask Boris Johnson if we can believe him

A Mumsnet user asked the prime minister: ‘Why should we believe anything you say when it’s been proved you’re a habitual liar?’ John Rentoul didn’t think much of it

The man himself got away with a fairly soft interview about how good he is at changing nappies (PA)

It was theatre, if you think throwing rotten tomatoes at a celebrity in the stocks is theatre. The opening question to Boris Johnson when he agreed to answer Mumsnet users’ questions was more of a statement: “Why should we believe anything you say when it’s been proved you’re a habitual liar?”

As questions go, it was strictly rhetorical, purely for effect. Indeed, it was logically pointless. If you start by telling someone they are a liar, you are saying that you do not believe anything they say, so there is by definition no way they can persuade you otherwise.

I don’t blame Justine Roberts, the founder of Mumsnet, who was putting the questions on behalf of her users. She said that the opening question was typical of about half the questions users had sent in, so she was merely the medium, not the messenger. But if there were so many similar questions, she could at least have chosen one that wasn’t quite so self-defeating. “Why do you think so many people think you are a liar, and how can you persuade them you are not?” would have been a more interesting question and it might even have elicited a more interesting answer.