Simon Lightwood said that “no one wants to see anyone striking” before giving his support to those workers looking for a pay rise.
Thousands of members of the National Union of Rail, Maritime and Transport Workers have walked out this week, bringing the UK’s rail network to a halt.
Millions of Britons have been forced to work from home as a result of the chaos caused by the industrial action, while teenagers sitting GCSE and A Level exams have faced difficulties getting to school.
Sir Keir has attempted to distance himself from the union action, refusing to endorse the strikes.
He has also sought to get his MPs to tow the party line and refuse to comment on the matter.
However, within just minutes of winning in Wakefield, Mr Lightwood appeared to undermine his leader’s request.
The newly-elected MP said workers had the right to seek better salaries.
He told Sky News: “Obviously, no one wants to see anyone striking.
“But, it’s important those workers receive the salaries that they can not only survive on, but live on.”
The Labour leader is currently grappling with how to deal with five members of his frontbencher team who disobeyed his orders not to join strikers .
He sent an email to shadow ministers and their teams at the start of the week reminding them not to be pictured on the picket lines.
More to follow…