Wigan MP and Labour frontbencher Lisa Nandy pictured visiting picket line

A photograph, tweeted by North West regional secretary of the Communication Workers Union (CWU) Carl Webb, appeared to show the shadow levelling up secretary meeting striking workers at a Wigan picket line.

The image was accompanied by the caption: “Thanks @lisanandy for taking the time to visit the @cwugmersey Wigan picket line this moring (sic) to speak to #TheCWU BT & Openreach members on strike and show solidarity”.

Ms Nandy’s visit comes in apparent defiance of Sir Keir Starmer saying Labour must move from being a “party of protest” to one that can win an election.

And it follows Ms Nandy giving her support to RMT members who have been holding rail strikes.

The Labour leader has said he supports people’s right to strike, but is seeking to contain a row with unions and the left wing of his party over his decision to sack Sam Tarry from the front bench after he gave broadcast interviews from a picket line.

Sir Keir, who previously banned frontbenchers from joining strikers on picket lines, said he fired Mr Tarry as a shadow transport minister after he booked himself on to media programmes without permission and made up policy “on the hoof” in defiance of the party’s “collective responsibility”.

But the move was met with fury by Labour’s left wing and trade unions.

Mr Tarry, MP for Ilford South, tweeted: “Great to see @lisanandy on the picket line. Senior Labour politicians need to demonstrate loud and clear that our Party is on the side of ordinary working people who are fighting back against this anti-worker Government.”

An ally of Ms Nandy said: “LOTO (Leader of the Opposition) were aware in advance. She went down to show her support for constituents campaigning for better pay and conditions at a really tough time, as you’d expect.

“As Keir said in the Mirror piece yesterday, we support their right to do that, and what they need now is a Labour government so they don’t feel like they’re on their own when times are tough.”

The PA news agency has contacted the Labour Party and Ms Nandy’s office for comment.