Transport secretary Louise Haigh has said the costs of HS2 have been allowed to “spiral out of control” and has launched an independent review to get spending back on track.

In 2013, HS2 was estimated at just £37.5bn (in 2009 prices) for the whole high-speed network, which included now-binned extensions from Birmingham to Manchester and Leeds.

But earlier this year, HS2 chair Jon Thompson admitted that costs for just Phase 1 (which will join Old Oak Common in west London to Birmingham Curzon Street and open around 2030) are now estimated to be between £49bn and £56.6bn at 2019 prices. Adjusting for inflation involves “adding somewhere between £8bn and £10bn”, he added.

Haigh blamed the soaring costs on a combination of poor project management, inflation and poor performance from the supply chain. She said the government would not look to resurrect Phase 2 of HS2, which was cancelled under the previous administration.

“The government recognises concerns about connectivity between Birmingham...