Chancellor of the Exchequer Rishi Sunak accidentally voted against the Government in a virtual vote on the Agriculture Bill.
Mr Sunak was among a “small number” of MPs who voted the wrong way as the new Commons remote voting procedure had its second outing.
The division list showed 22 Conservative MPs voted for the rebel amendment to the Bill, although they included Mr Sunak.
A source close to Mr Sunak blamed “online teething problems”, adding: “The Chancellor did not intentionally vote against the Government.
“He called the chief whip straight away to explain.”
I’m informed that their use of technology was not quite as good as they felt that it ought to be and that a few members have made a mistakeDame Eleanor Laing, Deputy Commons Speaker
After she announced the result of the vote, Deputy Commons Speaker Dame Eleanor Laing said: “I have been informed that there are a number of members, a small number of members, who have inadvertently cast their votes by electronic means in the opposite way to the way in which they had intended to vote.
“I’m informed that their use of technology was not quite as good as they felt that it ought to be and that a few members have made a mistake.
“There is no provision under the current temporary system by which a member can change their vote once it has been cast.
“But I am satisfied that even if a small number of votes had been cast in a different way, it does not affect the result of the division.”
The amendment, new clause 2, was an attempt by Tory MP Simon Hoare (North Dorset) to protect UK food standards under international trade agreements.
It was defeated by 51 votes, with 277 ayes and 328 noes.
The new temporary hybrid proceedings were introduced last month and have seen most MPs taking part in debates via webcam.
The voting system had its debut on Tuesday night with a “test” vote asking whether or not MPs believed the House had considered Covid-19 following a two-day debate on the pandemic.
Following the blunder, shadow environment secretary Luke Pollard could be heard asking in the chamber: “How many members of the Cabinet voted the wrong way?”
Government deputy chief whip Stuart Andrew was heard replying: “Just the one. He’s a very busy man.”
Earlier, during the vote on the amendment, Mr Pollard could be heard joking with Environment Minister Victoria Prentis: “Make sure you press the right button.”
She replied: “I have done. I think.”