Haigh said in a letter to Starmer dated yesterday, Nov 28, that she had told police she had lost the device during a “terrifying” mugging on a night out in 2013, only to discover later that the phone was still at her home.

In her resignation letter shared by Starmer’s office early today, Haigh said she was standing down as the issue “will inevitably be a distraction from delivering on the work of this government and the policies to which we are committed”.

“I remain totally committed to our political project, but I now believe it will be best served by my supporting you from outside government,” she said.

Starmer thanked Haigh for her work and for all she had done “to deliver this government’s ambitious transport agenda”.

Haigh is the first cabinet minister to resign from Starmer’s government, which has seen its approval ratings plunge since taking power in July.

Ministers have been criticised over the use of donations for clothing and gifts and for ramping up taxes on businesses and the wealthy in the government’s first budget.

Haigh said the incident with the phone was a “genuine mistake” from which she “did not make any gain”.