Dominic Cummings has made it his mission to scrap policies that are not good value for money

Boris Johnson’s most senior aide described HS2 as a “disaster zone” only days before the prime minister announced a review into whether it should be scaled back or scrapped entirely.

Dominic Cummings, former head of Vote Leave, raised concerns about the multibillion-pound high-speed rail project on Friday as he asked government advisers to highlight wasteful policies that could be cut.

A review into the scheme was announced yesterday and Grant Shapps, the transport secretary, said that ministers needed “clear evidence” before deciding whether it was “go or no go”. The review will consider the direct cost of “reprioritising, cancelling or descoping” HS2, which would link London to Birmingham, Manchester and Leeds.

It will also examine whether the £56 billion estimated cost is “realistic” after