Ms Soubry continued: “That was a terrible moment, I was there in the House.
“I’d never experienced anything like it.
“I was distressed by it and I’m a tough old bird frankly.
“It was appalling and I’m really worried about the language the Conservatives, in particular, will use in this election.
“And I want Boris Johnson to come out and make an absolute commitment that he will stay true to the traditions of British politics that we do it robustly and with rigour, but we do it with decency.”