Keir Starmer has fired a warning shot to rebellious Labour MPs and moved to reassert his grip on his party by removing the whip from four backbenchers for repeatedly breaching discipline.

Labour MPs Rachael Maskell, Neil Duncan-Jordan, Brian Leishman and Chris Hinchliff were told they had lost the party whip on Wednesday afternoon for repeatedly rebelling against the government.

A Labour source told the Guardian the whip was being removed from “persistent rebels”, while a further three Labour MPs were stripped of their government trade envoy roles.

The surprise move, which came after Downing Street pledged to mend relations with the Labour backbenches after being forced to U-turn over controversial welfare cuts, triggered fury in sections of the parliamentary party.

All four MPs who were suspended have been openly critical of several government policies. Maskell and Duncan-Jordan spearheaded opposition to the cut to the winter fuel allowance and welfare reforms. Hinchliff organised a rebellion over the government’s flagship planning bill, voicing concerns about its effect on nature.

Three other Labour MPs who have rebelled against the party whip – Rosena Allin-Khan, Bell Ribeiro-Addy and Mohammad Yasin – had their trade envoy roles removed.

The decision was met with dismay from Labour backbenchers, who said No 10 had “learned nothing” from the rebellion against its welfare bill, in which ultimately 47 Labour MPs broke the whip despite the major concessions made by ministers. Starmer was accused of being aloof and disconnected from his MPs’ concerns in the wake of the row.

One MP on the Labour left said those suspended had been told they faced an inquiry lasting a few months and that the decision had come from Downing Street.

The MP said the move was intended to create a “climate of fear” in the parliamentary party and made the government look “brittle”. “What those MPs did, what we all did, was to defend Labour values,” they said.

“The fact that the government was humiliated was all of [its] own making. There are elements around No 10 who now want to lash out vindictively rather than acknowledge the mistakes that were made. This is now frankly a punishment beating … They’ve learned nothing. There’s no sense of self-analysis or reflection about how they could have done better.”

Another Labour MP said: “Labour MPs now return to their constituencies for the summer totally demoralised by these petty and vindictive actions. I’m afraid if we have more arguments when we return on special needs provision and the lifting of the two-child cap, then things will only get worse. It’s dreadful politics and risks jeopardising the opportunity that such a massive majority presents.”

A third Labour MP said: “The trade envoy sackings are particularly weird … There are Tory and Lib Dem trade envoys who vote against the government all the time and that’s OK, but a Labour one gets sacked for one rebellion? Make it make sense.”

All four suspended MPs issued statements saying they wanted to remain in the party in response to rumours that they were in talks to defect to rival groups, such as the breakaway party being formed by Jeremy Corbyn and Zarah Sultana.

MPs who lose the whip are no longer considered part of the parliamentary party, though they retain party membership unless that too is revoked. The suspension is usually for a set period, and then reviewed.

Maskell, who was a shadow cabinet minister under Jeremy Corbyn, said she had been suspended for “standing up for my constituents” over the benefits plans and that she was “upset that we are in this place because I believe we are better than that as a party”.

Of the other three suspended MPs, all of whom are from the 2024 intake, Leishman is a member of the leftwing Socialist Campaign Group of Labour MPs, while Duncan-Jordan and Hinchliff were both elected with very slim majorities in seats that have never before returned Labour MPs.

Hinchliff said he was “proud to have been elected as a Labour MP and I hope in time to return to the Labour benches. In the meantime I will continue to fight every day for the needs of my constituents and nothing will change in how I engage with and represent those I was elected to serve”.

Leishman said he wanted to “remain a Labour MP and deliver the positive change many voters are craving”.

“I have voted against the government on issues because I want to effectively represent and be the voice for communities across Alloa and Grangemouth. I firmly believe that it is not my duty as an MP to make people poorer, especially those that have suffered because of austerity and its dire consequences”.

Duncan-Jordan said he had “consistently spoken up for my constituents on a range of issues, including most recently on cuts to disability benefits. I understood this could come at a cost, but I couldn’t support making disabled people poorer.”

Some MPs were privately scathing after an email was sent round the parliamentary Labour party from Jessica Morden, its chair, wishing colleagues a “relaxing break” and congratulating them for a “phenomenal” output just hours after the suspensions.

This is the second time Starmer has enforced severe discipline on MPs who vote against his government, after removing the whip from seven MPs who voted with the Scottish National party to remove the two-child benefit cap in the king’s speech last summer.

Those suspended from the whip last July included John McDonnell, Richard Burgon, Ian Byrne, Rebecca Long-Bailey, Imran Hussain, Apsana Begum and Zarah Sultana.

The whip has since been restored to most of those MPs, though several on the left have continued to vote against the government on a number of issues including welfare, the proscription of Palestine Action and on changes to planning.

Several of the leftwingers suspended last summer attacked the move. Burgon, the Labour MP for Leeds East, said ministers needed to change their approach “to help stop a Reform government”. Byrne, the Labour MP for Liverpool West Derby, said he was “appalled” by the suspensions as they risked “damaging Labour’s support and risk rolling out the red carpet for Reform”.

Steve Wright, the general secretary of the Fire Brigades Union, called the move a “dangerous and authoritarian act”.