The new Montgomeryshire and Glyndŵr MP has apologised after swigging a carton of milk in the House of Commons.

Labour’s Steve Witherden apologised for the gaff dubbed ‘milkgate’, but that he wouldn’t “be ashamed of supporting British dairy farmers”.

The thirsty MP explained he was still learning the chamber rules, which includes strictly no food or drink other than water in the chamber, adding that milk was “an excellent source of protein”.

Tory frontbenchers spotted Witherden taking a swig last week and tipped off the Deputy Speaker, who told the Labour Whip.

Moments later, Witherden was no longer in his seat.

Witherden’s spokesperson said: “Milk is an excellent source of protein and calcium and can be a nutritious part of a balanced diet.

“Like many new MPs he is still learning the rules, but he would certainly not be ashamed of supporting British dairy farmers, considering how badly they were let down by the last government.

“The Conservatives underspent the agriculture budget by £358m over the last three years, and 12,000 farms closed during their 14 years in office.”

Sources say Witherden has since been given the Westminster nickname ‘Ernie’, after the Benny Hill song about the fastest milkman in the West.