HS2 is an "appalling mess" and will not be completed by its target date of 2033, the transport secretary has said.
Heidi Alexander blamed the Tories for what she described as a "litany of failure" surrounding the high-speed rail project, saying costs had soared by £37bn and multiple deadlines had been missed.
She said this meant there was "no route" to delivering the London to Birmingham leg of the scheme on schedule. However, she did not say when it might open or how much it would now cost.
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In a Commons statement, Ms Alexander said: "After a decade and a half of Tory timelines planned then delayed, routes drawn up then cancelled, budgets calculated then blown, promises made then broken, we inherited a project that has lost the trust of the public, created an image of a Britain woefully unable to deliver big infrastructure and axed swathes of the country it was meant to serve."
She added that despite the project being downsized – with routes to Leeds and Manchester cancelled – it could still become "one of the most expensive railway lines in the world, with projected costs soaring by £37bn" from when it was approved in 2012 to when the Tories lost the general election last year.
However, Ms Alexander claimed Labour would turn the project around.
It came amid calls from Reform UK's leader to cancel the project entirely. Nigel Farage said he had campaigned against HS2 since it was proposed in 2010, when it had a price tag of £35bn and a target opening date of 2026.
He said: "Has the moment not come, rather than having another reset, to recognise this is a failure?
"Let's scrap HS2, let's use the tens of billions of pounds we can save in the next decade to upgrade railway lines across the entirety of the United Kingdom."
But Ms Alexander said cancelling it would be a "waste" of the more than £30bn already spent, and said there were "significant capacity constraints between Birmingham and London" that HS2 could address.
She said the government had already appointed a new chief executive of HS2 Ltd, Mark Wild, who had been tasked with "building the rest of the railway safely at the lowest reasonable cost, even if this takes longer".
Mr Wild published an interim report on Wednesday examining HS2's failures to date, which found there was an "accumulation" of issues over time but no "no single root cause" for its rising costs and delays.
Another report by infrastructure delivery specialist James Stewart looked at what lessons could be learnt, with the government accepting all of its recommendations.
Ms Alexander also addressed allegations of fraud involving some of those involved in the project, saying they would be investigated and, if proved, "consequences will be felt".
"It's an appalling mess but one we can sort out", she added.
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Wednesday's announcement was the latest setback in the beleaguered project.
The initial plan was to build the first phase connecting London and Birmingham, followed by adding two branches to Manchester and Leeds.
However, Boris Johnson scrapped the leg to Leeds in 2021, while Rishi Sunak pulled the plug on the remainder of the second phase to Manchester in 2023.
The original bill for the entire project at 2009 prices was supposed to be £37.5bn.
The most recent cost estimate for phase one only was well above that – at £49bn to £56.6bn (in 2019 prices),
Shadow transport secretary Gareth Bacon accepted mismanagement on behalf of his party.
He said cutting the northern legs was a "product of mistakes we made in the handling of HS2" and "we must learn from those mistakes and we must not repeat them".
(c) Sky News 2025: HS2 an 'appalling mess' and will be delayed again, transport secretary says