HS2 chief operating officer Richard Robinson is to leave the project after a year in the role.
Construction News understands the former Aecom chief executive of civil infrastructure has resigned.
The move comes while the future of HS2 is being reviewed by a team chaired by Doug Oakervee, after prime minister Boris Johnson called for a review of the project.
The review is examining the entire future of the project including its business case, costs and route.
HS2 chief executive Mark Thurston said: “We can confirm that chief operating officer Richard Robinson has decided to leave HS2 Ltd to take up a new senior role in the private sector.
“We wish him every success in his new position.”
According to HS2, more than 150 land acquisitions were completed in July and August under Mr Robinson’s leadership.
It is understood that the role is to be covered by existing staff in the short term.
Mr Robinson joined HS2 on 24 September 2018.
Last week the project formally awarded the contract for the £1bn Old Oak Common build to a Balfour Beatty / Vinci / Systra joint venture, after wrangling which followed a legal dispute over the procurement.
In June, Mr Robinson defended HS2’s procurement strategy, saying that it had been looking for the best bids not necessarily the cheapest when it came to awarding work on the project.
However a stocktake by programme chair Allan Cook released earlier this month, which warned that the project would cost more than its £56bn budget and not be delivered by 2026, also said that procurement strategies should be changed in future.