Sir Keir Starmer has suspended York MP Rachael Maskell from the Labour Party as part of a purge of “troublesome backbenchers”.
Ms Maskell, who spearheaded plans to halt the Government’s welfare reforms, has lost the whip, alongside Neil Duncan-Jordan, Brian Leishman and Chris Hinchliff.
All voted against the Government’s benefits reforms as part of a wider rebellion earlier this month.
The York Central MP said she had been suspended for “standing up for my constituents” over the benefits plans.
Ms Maskell said she had had a “positive conversation” with the chief whip, adding: “He knows my heart and why I did what I did.
“I explained there are lines I can’t cross because of where I come from in politics with my faith.”
She said she was “not angry” but “upset that we are in this place because I believe we are better than that as a party. I believe that strength comes from the backbenches.”
A Labour backbencher described the suspensions as “devastating” and said they did not signal a willingness from the Government to reset relations with the parliamentary party.
As well as the suspensions, three other MPs have been removed from trade envoy jobs: Rosena Allin-Khan, Bell Ribeiro-Addy and Mohammad Yasin.