Labour leader Sir Keir Starmer has said one of his shadow ministers was sacked yesterday for making up policy “on the hoof” as he stood on a picket line during rail strikes.

Sam Tarry was dismissed from his role as a junior shadow transport minister after he disobeyed orders for frontbench Labour MPs to not appear on picket lines during Wednesday’s rail strike.

He told Sky News workers should be offered pay rises in line with inflation – however Labour’s position is that pay negotiations are for unions and ministers.

Speaking for the first time since he was sacked, Sir Keir explained: “Sam Tarry was sacked because he booked himself onto media programmes without permission and then made up policy on the hoof.

“That can’t be tolerated in any organisation because we have got collective responsibility, so that was relatively straightforward.”

“Of course, as far as the industrial action is concerned, I completely understand the frustration of so many working people who have seen the prices go up, have seen inflation through the roof and their wages haven’t gone up.

“So the Labour Party will always be on the side of working people but we need collective responsibility as any organisation does.”

Earlier, former shadow chancellor John McDonnell, who is still an MP, told Sky News he was backing Mr Tarry’s position and criticised Sir Keir for sacking him.

He said it was a “severe mistake” as the Labour Party was formed by the trade unions “so when the trade unions have a just cause, we support them – and this is a just cause”.