“I have only one comment about the proposed subject matter,” reads the email from Bercow’s agent. “For good reasons John will not agree to answer questions about bullying allegations, or bullying in general.

“So long as you confirm today (in writing, please) that Stephen will stay clear of that topic altogether, we’re good to go ahead.”

BBC sources said that request was subsequently refused by the show’s producers.

In a follow up email, Bercow’s agent was unapologetic about cancelling the interview because of the failed demand. “Just to wrap this up, [redacted], it’s definitive ‘no’ from John Bercow as a result of this morning’s conversations,” he wrote.

“’I’m pleased to say we’re doing a number of foreign press and media interviews, and a 130-strong session with the FPA (Foreign Press Association), so those around the world who are interested in hearing John’s views will get the opportunity.”

In a statement to BuzzFeed News, a BBC spokesperson said: "In accordance with BBC editorial policy, Hard Talk does not accept any preconditions from interviewees as to what questions can be asked."