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”.