The “final decision” to axe HS2’s northern leg was taken during Tory conference, Downing Street has insisted, despite a video appearing to show Rishi Sunak outline the move days earlier.

No 10 defended the Prime Minister over the recording, which prompted questions about his repeated refusal to confirm the fate of the railway line in the run-up to his keynote speech in Manchester.

In the clip, which was posted by Mr Sunak on X and appears to have been filmed in Downing Street before he left for conference, he says: “I’m stopping all phases of HS2 beyond Birmingham.”

Mr Sunak’s official spokesman suggested the video was “preparatory work” done ahead of the major policy change being agreed on by Cabinet shortly before it was announced.

The official said on Monday: “As is a longstanding part of the process for announcing major policy decisions, it’s right that preparatory work takes place.

“That might be the preparation of documents, command paper documents, or communications products, to explain the decision to the public, obviously all of that is done on the understanding it is done in advance of a final decision being taken.”

He insisted that the “final decision was taken at Cabinet, by Cabinet” on the morning of Mr Sunak’s speech.

There had been speculation throughout September that the change was coming, but ministers refused to confirm it until Mr Sunak made the announcement at conference, while Parliament was in recess.

“The House is being updated at the earliest opportunity. You’ll know that policy announcements are regularly made at party conferences. I don’t think this is any different,” the Prime Minister’s spokesman said.

The Prime Minister defied senior Tories and business leaders to scrap HS2 from Birmingham to Manchester, saying “the facts have changed” and the cost of the high-speed rail scheme had “more than doubled”.

He instead pledged to reinvest the £36 billion the Government expects to save by axing the Manchester line into other new transport projects “in the North and the Midlands, across the country”.

Speaking in the Commons on Monday evening, shadow transport secretary Louise Haigh said: “There is only one man who should take responsibility for the sheer chaos, incompetence and desperation we have seen over the past two weeks and that is the Prime Minister.

“Only he could announce the cancellation of HS2 to Manchester, in Manchester.”

Ms Haigh pressed Transport Secretary Mark Harper about whether a meeting took place with top civil servant Simon Case ahead of the decision to scrap the rail project, adding: “And what of the economic impact? How many businesses does he expect to go under as a result?”

Mr Harper said: “I took the formal decision the day before the Prime Minister’s speech. There was a meeting of the Cabinet on the morning of the Prime Minister’s speech which approved that decision, and the Prime Minister then announced it shortly afterwards.”

On HS2, he earlier said: “With decades to wait before it arrived, and benefits dwindling, it risked crowding out investment in other transport areas and no longer reflected post-pandemic changes in travel.”

Conservative MP Greg Smith welcomed the move to ditch the northern leg of HS2 but said it would leave a “legless stump” through his Buckingham constituency from London to Birmingham.

He asked Mr Harper if he will “scrap the entirety of HS2”, with the Transport Secretary defending the Government’s decision.

Conservative former business secretary Greg Clark expressed “dismay” and “shame” that the UK is unable to “connect our great cities when other major countries around the world are able to do so”.

He said: “Wouldn’t the right thing be to address the costs of these schemes, why they’re so much more expensive in this country rather than to scale back our ambitions?”