Keir Starmer has been dealt a blow to his authority after Labour frontbenchers defied him to appear alongside striking railway workers on picket lines.
The leader’s office sent an email to members of the shadow cabinet urging them to tell their teams not to join the pro-strike demonstrations.
It said: “We do not want to see these strikes to go ahead with the resulting disruption to the public.”
The message added: “However, we also must show leadership and to that end, please be reminded that frontbenchers including [parliamentary private secretaries] should not be on picket lines.
“Please speak to all the members of your team to remind them of this and confirm with me that you have done so.”
One shadow cabinet member told HuffPost UK: “It’s a sensible decision given Tories want to blame us for their failings. We mustn’t fall into their trap.”
But just hours into the first day of the RMT rail union’s industrial action, two Labour frontbenchers had tweeted pictures of themselves on the picket line.
The first was Kate Osborne, who is a parliamentary private secretary to shadow Northern Ireland secretary Peter Kyle.
She tweeted: “On the picket line at Bromley. I’m a trade unionist, I will always stand on the side of the workers. Solidarity.”
The next to publicly break ranks was Labour whip Navendu Mishra, who is MP for Stockport.
He tweeted: “This treacherous government has underfunded & mismanaged our public transport network for more than a decade. As a proud trade unionist, I stand with all workers on our railway network who are taking industrial action to fight for their jobs & keep passengers safe #RailStrikes.”
Paula Barker, the Labour MP for Liverpool Wavertree and a PPS in the opposition defence team, was on the same picket line.
She tweeted: “Proud to support the workers on the picket line at London Victoria this morning, alongside colleagues. These workers keep our country moving safely 365 days a year. The least they deserve is to be paid properly and feel secure in their jobs.”
Meanwhile, shadow environment minister Alex Sobel stood alongside striking London Underground workers on a picket line at Tottenham Court Road.
Thousands of railway workers have today gone on strike in a dispute over pay, jobs and conditions.
Further walkouts are planned for Thursday and Saturday, with union bosses warning the dispute could go on for months
Labour chief whip Alan Campbell will decide after Saturday’s strike action what disciplinary action - if any - to take against Labour frontbenchers on RMT picket lines.
The Conservatives have labelled the industrial action “Labour’s strikes” in an attempt to pin the blame for the walkouts on the opposition.
But a Labour spokesperson said: “Unlike the government, our focus is firmly on the public. The Tories are in charge, and they failed to fix it. The responsibility for this week’s chaos lies firmly with them. Boris Johnson and Grant Shapps must u-turn on their refusal to even meet with Network Rail and the RMT to urgently find a solution.”