A number of Labour MPs have joined picket lines to support striking workers, despite party leader Keir Starmer previously saying no MP should be on a picket line “if they want to be in government”.

The official Conservative Party press office account shared tweets from 13 Labour MPs such as Richard Burgon, Ian Lavery and Kate Osborne joining picket lines during Wednesday’s strikes.

The thread was prompted by the quote from Sir Keir in an interview with Sky News in August last year.

Left-winger Sam Tarry, the former frontbencher who represents Islington South, was previously sacked as a shadow transport minister after giving interviews from a picket line in July last year.

He defended his decision to join striking teachers in his constituency, and responded to the Tory party press office’s twitter thread by saying: “Much rather you focused on fairer pay for front line workers than me standing on picket lines… as Labour MPs have done so for over a 100 years.”

Former shadow chancellor John McDonnell told the PA news agency he believed Labour MPs should be on the picket lines, as he joined striking workers outside the Treasury and various locations in his constituency of Hayes and Harlington.

Former party leader Jeremy Corbyn also declared his support for the strikes, tweeting: “They are striking for decent pay. They are striving for social justice. They are fighting for us all.”

The Public and Commercial Services Union (PCS) tweeted their thanks to Labour MPs who attended picket lines on Wednesday.

Sir Keir previously declined to say whether he would cross any picket line at Parliament during the civil servants’ strike.

Labour has been approached for comment.