Philip Hammond is fighting to save his career after being forced into the most humiliating Budget U-turn in a generation.

Theresa May scrapped the Chancellor’s headline policy - a hike in National Insurance contributions for the self-employed - after a backbench rebellion over what amounted to a broken manifesto pledge.

Tory MPs said the fiasco had been “hugely damaging” to Mr Hammond’s authority, with one saying he was now “on probation”.

With Mr Hammond now looking increasingly isolated from Number 10, a Conservative source said the Prime Minister had “dug her stiletto in and told him, ‘We are reversing this – I don’t care how bad it is for you’.”