HS2: Fewer seats could force passengers not to travel

The NAO report also said that disposing of the land and property bought along the northern leg of the route could take several years, although some may be needed for other transport projects such as Northern Powerhouse Rail.

The recent King’s Speech included a High Speed Rail Bill, which had previously been tabled to build HS2’s northern leg.

The new Labour government said it would not revive HS2’s cancelled sections but repurpose the bill to bring in powers to build new rail infrastructure in northern England.

“We are reviewing this report’s findings, alongside the position we have inherited on HS2 and wider transport infrastructure and will set out next steps in due course,” Ms Haigh said.

“Transport is an essential part of our mission to rebuild Britain – and we’re committed to delivering infrastructure that works for the whole country.”

The authors of the NAO report said there would be more costs to come on top of the cancellation, which is expected to take three years and cost £100m.

Some work will be done even though it is no longer required.

For example, only three platforms will now be needed at Birmingham Curzon Street, but the full seven will be built because it would cost more to cancel.

Since 2020, construction costs have increased by £6.1bn.

The NAO report says the DfT and HS2 Ltd are finalising a “lowest cost action plan” to try to reduce costs, particularly through trying to renegotiate contracts.

A spokesperson for HS2 Ltd said: “This is a project of unprecedented scale and complexity and the cancellation of Phase 2 has increased our cost challenges.”

Reasons include the budget and schedule being set too early, delays to planning consent and the impact of external events such as the Covid-19 pandemic.