Several Labour backbenchers, including former party leader Jeremy Corbyn, have joined the picket line in Liverpool with the dockworkers.
Sir Keir Starmer and his shadow cabinet claim they want to help workers by gaining power, thus they will not be joining the protesters.
Mr Corbyn has been suspended from the party.
The MPs pictured with him include Richard Burgon, Zarah Sultana, Nadia Whittome, and Lloyd Russell-Moyle.
RMT General Secretary Mick Lynch is also in the picture.