David Dimbleby tries - and fails - to mock Tory MP Jacob Rees-Mogg for being posh

The Conservative MP's exchange with the Question Time chair over his attendance of Eton College entertained the audience in Slough

The Question Time audience were treated to a fine exchange of wit during a debate when Conservative MP Jacob Rees-Mogg hit back at a remark by David Dimbleby referring to his Eton education.

Answering a question about whether expansion of Heathrow would create the number of jobs promised and justify the cost to the environment, Mr Rees-Mogg told the audience in Slough that he too could relate to their plight - despite believing that a third runway should “absolutely” be built at the airport.

“Heathrow is the most convenient London airport,” he said to a dismayed audience.

“I realise that in Slough this may not please everybody. I used to live not a million miles from Slough with the airplanes going over. I must confess they did not prove too bothersome there.”

To which Mr Dimbleby replied: “Eton, is that?”

“That’s absolutely right,” the MP replied.

Before adding: “I was at school with your son.”

Fellow panellist Piers Morgan called Mr Rees-Mogg’s quip “fantastic” and said “that’s the best thing I’ve seen him take in a long time”, pointing to Mr Dimbleby.

The 46-year-old MP then added: “Let’s get back to the important subject of Heathrow rather than mine and Henry Dimbleby’s education.”

Earlier, Mr Dimbleby had caused more laughter after reprimanding Mr Morgan for referring to Question Time as a “show” rather than a “programme”.

Mr Rees-Mogg, MP for North East Somerset, read history at Trinity College, Oxford University, after attending Eton College.

Mr Dimbleby, who has chaired Question Time for 21 years, was educated at Glengorse and Charterhouse schools, before reading philosophy, politics and economics at Christ Church, Oxford University.