It emerged yesterday that Haigh pleaded guilty to an offence related to incorrectly telling police that a work mobile phone was stolen in 2013.

In her resignation letter to the Prime Minister today Haigh said: “I appreciate that whatever the facts of the matter, this issue will inevitably be a distraction from delivering on the work of this government and the policies to which we are both committed.”

Kier Starmer replied: “Thank you for all you have done to deliver this Government’s ambitious transport agenda.

“You have made huge strides to take our rail system back into public ownership through the creation of Great British Railways, investing £1 billion in our vital bus services and lowering cost for motorists.”

Haigh launched a major costs crackdown on HS2 last month and said she is “reinstating ministerial oversight of the project to ensure greater accountability.”