A Labour frontbencher has been sacked after giving media interviews on a picket line in support of striking rail workers.
Shadow transport minister Sam Tarry breached "collective responsibility" rules, and has been "removed" as a result, the party said in a statement this afternoon.
Leader Sir Keir Starmer had previously told frontbenchers not to join picket lines.
News of the sacking sparked an immediate backlash, with MPs breaking ranks to voice their support for Mr Tarry, who had been in post since January last year.
A party spokesperson said: “The Labour Party will always stand up for working people fighting for better pay, terms and conditions at work.
“This isn’t about appearing on a picket line. Members of the frontbench sign up to collective responsibility. That includes media appearances being approved and speaking to agreed frontbench positions.
“As a government in waiting, any breach of collective responsibility is taken extremely seriously and for these reasons Sam Tarry has been removed from the frontbench.”
In a statement, Mr Tarry said: "These key workers kept our train services running throughout the pandemic, and were among Britain's Covid heroes alongside the NHS and other public services.
"Those same workers have been forced to take action because they're faced with a cost-of-living crisis and rampant inflation caused by the Government's mismanagement of our economy, leaving millions struggling to pay their bills and provide for their families, made worse by the fact that callous and incompetent ministers refuse to even negotiate with their trade unions.
"This dispute would not be taking place under a Labour government, which would ensure that rail workers receive a fair wage.
"It has been a privilege to serve on Labour's frontbench for the past two years and to have had the opportunity to speak up for hard-pressed workers who deserve so much better than the treatment they've received from this corrupt and out-of-touch Government.
"I remain committed to supporting the striking rail workers, and campaigning for a Labour victory at the next general election, which I will fight for relentlessly from the backbenches."
The move sparked anger within the party, with Labour MP Kate Osamor tweeting: "Solidarity @SamTarry. The Labour Party exists to fight for ordinary people. We must never lose sight of that."
Fellow MP Zarah Sultana wrote: "Labour MPs should be proud to stand with workers. The clue is in the name. Solidarity @SamTarry."
And Manuel Cortes, general secretary of trade union the TSSA, said in a statement: "Today Sam did the right thing and stood shoulder to shoulder with rail workers striking for fairness and safety at work.
“Whatever excuses the Labour Party makes about the reasons for Sam being sacked, the reality is that Sam has shown solidarity with his class and we applaud him for that.
"The Labour Party needs to wake up and smell the coffee. If they think can win the next general election while pushing away seven million trade union members, they are deluded."
Earlier today Mr Tarry posted pictures of himself joining striking workers and union bosses in London.
He told ITV's Good Morning Britain: "If we don't make a stand today, people's lives could be lost.
"Some of the lowest-paid workers are on strike today in the rail industry, safety-critical workers, workers who make sure our railways get people to work and do so safely.
"It can't be accepted anymore that people just have to accept that inflation is out of control. The Government's doing nothing on the cost-of-living crisis."
Asked whether he expects to be sacked by Sir Keir, Mr Tarry said: "I've no idea what Keir will decide to do but I know this - if Keir was in government right now, this dispute wouldn't be happening."
He added: "I have absolutely 100% confidence that any Labour Party MP would be in support of striking workers who have given up a day's pay, a week's pay or even longer."
Mr Tarry also told Sky News that he was "not defying anybody", but was supporting "40,000 low-paid transport workers".
Yesterday Sir Keir said: "The Labour Party in opposition needs to be the Labour Party in power.
"And a government doesn't go on picket lines, a government tries to resolve disputes."
