HS2 chief executive Simon Kirby has revealed he will quit the project to join Rolls-Royce as its chief operating officer.
The decision from Mr Kirby, who was appointed to head the construction of the £55.7bn line in 2014, comes days before a public accounts committee report on the preparation for delivering the project is published.
The former boss of Network Rail’s infrastructure projects division will join up with Rolls-Royce in the coming months.
His impending departure comes ahead of a decision from transport secretary Chris Grayling on the government’s commitment to the second phase of the line from Birmingham to Manchester and Leeds.
Europe’s largest infrastructure project has come under increasing pressure following a National Audit Office report in June.
The report called the timetable for delivery of HS2 “too ambitious” and for the delivery of phase one of the line to be pushed back one year.
It also revealed that HS2 was facing cost pressures, with estimates for the £27.4bn first phase currently exceeding available funding by £204m, while phase two is exceeding available funding by £7bn.
The search will now be on for HS2 to appoint a new chief executive as quickly as possible ahead of key milestones in procurement of the project.
The procurement for phase one of the lines is reaching its climax, with the winners of the three £900m enabling works expected to be picked next month.
This comes ahead of HS2 achieving royal assent, expected later this year, and the awarding of the £11.8bn of civils packages next spring.
HS2 has appointed former Amey chief executive Mel Ewel as a non-executive director of the company.
He will sit on the organisation’s board and help with the project as it moves into construction phase.
Mr Kirby said on his impending departure: “HS2 is not just a highly ambitious project, but also one which will leave a lasting legacy for Britain.
“It has been, therefore, a huge honour to have been its chief executive and to have been involved in creating a leadership team made up of the best talents from this country and elsewhere.
“I have absolute confidence in their ability to deliver the project and, in doing so, to help transform the way we do things in this country.”
HS2 chairman Sir David Higgins said: “Whilst naturally we will miss his experience and leadership, I also recognise that [Simon Kirby] is joining a truly great, global company in an industry in which he has previously worked.”
Rolls-Royce chief executive Warren East said: “His exceptional track record in delivering complex major programmes is highly relevant to Rolls-Royce and will strengthen management capability ahead of a period of significant expansion.”