Keir Starmer has proven he’s ruthless and dislikes being challenged

This Government favours the rehabilitation of ex-offenders. Except when it comes to Cabinet ministers. Louise Haigh was forced to resign after it emerged she had pleaded guilty to a criminal offence in 2014 for incorrectly telling the police a work mobile phone had been stolen.

She was given a discharge, the lightest of all reprimands, which is now spent. The offence took place before she was elected an MP. If this is the bar for a ministerial resignation then it is so low that Keir Starmer may as well appoint a cabinet of Munchkins.

Surely this was a storm which could have been ridden out if, and it is a big if, the PM had been so minded. He could have noted the historic nature of the offence and drawn a comparison with Boris Johnson and Rishi Sunak receiving police fines when in office.

Starmer’s reluctance to defend Haigh may be because there is more to this than has been divulged. Perhaps there is another skeleton in the cupboard. But her summary dismissal suggests she was guilty of another crime – the heresy of representing the soft left around the Cabinet table.

Haigh did not just earn her Red Lou nickname for her eye-catching hair dye. She was one of the few Cabinet ministers to raise objections ahead of the Budget about the proposed spending cuts. The former transport secretary was also given a dressing down by No 10 after she called for a boycott of P&O Ferries just as the government was trying to secure a £1billion investment from the firm’s parent company.

Many Labour MPs will have clocked that Starmer’s letter to Haigh was terse to the point of rudeness. This may not matter now but it could cause the Labour leader problems further down the line given that Haigh is well-liked by parliamentary party colleagues.

She was also good at her job. The reason she became a Cabinet minister at 37 was because she had mastered her brief and knew what was needed to repair Britain’s creaking transport network.

In her brief spell in charge she oversaw the renationalisation of the railways, ended the strikes and secured new employment protections. Starmer has shown he is ruthless but also doesn’t like to be challenged. Unlike Tony Blair, who had dissident voices around his Cabinet table such as Clare Short.

Few left-wingers are in the PM’s top team. Haigh’s exit may be a precursor for a purge of other soft-left figures. Appointing Heidi Alexander as her replacement points to only one direction of travel. Cabinet ministers will have noted the PM’s reluctance to back a colleague in difficulty. He may not need Cabinet loyalty now but he is almost sure to in the future.