The deputy chair of the government’s review of the controversial High-Speed 2 (HS2) project has said he will have “no opportunity to influence conclusions” made in the final report.

Labour peer Lord Berkeley claimed on Twitter on Friday that his role in the review has “finished” but that the report is not complete.

He also said he has been told that once the final report is finished by chair Douglas Oakervee and the Department for Transport (DfT) secretariat, “it will be locked into the DfT vaults for the new [secretary of state] to publish”.

Lord Berkeley’s comments come as the UK prepares for a fresh general election in December, which could lead to the appointment of a new secretary of state for transport.

Current transport secretary Grant Shapps launched the review in August, saying the exercise would result in a “go or no-go” decision by the end of the year.

A spokesman for the DfT told BBC News the review “will conclude in the autumn” but would not confirm when the report will be published.

In September, Shapps received a report from HS2’s newly appointed chairman Allan Cook, which confirmed the project was around £20 billion over budget and that its first phase linking London and Birmingham would be delayed by up to five years.

Construction along the Phase 1 route has continued throughout the review.

Earlier this year, the BBC obtained documents from 2016 that showed the government was likely informed that HS2 was over budget and behind schedule but did not release the details to Parliament ahead of a key vote to give the project the go-ahead.

Lord Berkeley is a civil engineer who worked on the construction of the Channel Tunnel. He is a critic of HS2, and the government has previously said his appointment as deputy chair proved the review would consider all options for the future of the project, including scrapping it altogether.

But critics have questioned the independence of review lead Oakervee, who is a former chairman of HS2 Ltd, the company in charge of the project.

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