Diane Abbott appeared to mock Keir Starmer by joining striking RMT rail workers on the picket line.
A leaked Labour memo told MPs not to join picketing rail workers striking today after turning down a pay rise.
But some MPs appear to have ignored this warning.
Former shadow cabinet member under Jeremy Corbyn, Diane Abbott joined the strike and even taunted the Labour leader while doing it.
She tweeted: "On the RMT union picket line at the Seven Sisters depot.(But don’t tell Keir Starmer)."
Diane Abbott Jeff Overs
Labour whip Navendu Mishra also joined a picket line, saying: “As a proud trade unionist, I stand with all workers on our railway network who are taking industrial action to fight for their jobs and keep passengers safe.”
It was understood Sir Keir was waiting until the end of the industrial action before instructing chief whip Alan Campbell to deal with disciplinary issues.
Labour did not say whether or not the MPs could lose their frontbench roles as a result, with a spokeswoman saying: “Unlike the Government, our focus is firmly on the public.”
The opposition party was cautious not to give credibility to the Government’s claims it is playing a role in the strikes, but is also coming under pressure from unions to stand up for workers’ rights.
Sharon Graham, general secretary of the Unite union, said: “The Labour Party was founded by the trade unions and we expect Labour MPs to defend workers, by words and by actions.”
Undated handout file photo issued by the Sharon Graham Campaign of Unite general secretary Sharon Graham Sharon Graham Campaign
Scottish Labour leader Anas Sarwar, who sits in the Scottish Parliament, put distance between himself and Sir Keir’s position by heading to a picket line to show his “solidarity”.
“The workers don’t want strikes. The unions don’t want strikes. The public don’t want strikes,” he said.
Instead of giving his unequivocal support to the workers, Sir Keir has sought to blame the Government for the walk-outs as he insists he did not want strikes to go ahead.
But deputy leader Angela Rayner gave clear backing to the industrial action, tweeting: “Workers have been left with no choice.
“No one takes strike action lightly. I will always defend their absolute right to do so for fairness at work.”