HS2s chairman, Sir David Higgins, is to become chairman of Gatwick next month, leaving the £55bn high-speed rail project with an increasingly occupied figurehead and no permanent chief executive.
Higgins, who also spends time working in Australia as a director of the Commonwealth Bank, will take over from Sir Roy McNulty on 1 January at the Sussex airport.
He is paid £240,000 for three days a week at HS2 and is understood to be remaining in post as chair for up to a year, until a replacement is found and as the search for a new chief executive continues.
The previous chief executive, Simon Kirby, whom Higgins brought over from Network Rail on a salary of £775,000, announced his departure in September for a more lucrative role at Rolls-Royce.
Earlier this week Higgins told the transport select committee that HS2 should consider offering loyalty bonuses to ensure its top people stayed in the job.
He told MPs on Monday: It is always difficult to talk about bonuses in the public sector
but we should look at some sort of bonus over a period of years that encourages people to stay it is something we should consider.
Higgins was chief executive of the Olympic Delivery Authority from 2005-11 and ran Network Rail from 2011-14.
Gatwick is continuing to invest and remains poised to push its claim for a second runway should Heathrows planned expansion be blocked by parliament next year.
Higgins said Gatwick had made remarkable progress in recent years: Whilst the case for Gatwick expansion in the future remains very strong, the challenge for Gatwick now is to continue to invest so it can maximise the use of its existing facilities and so can do even more for Britain in the coming years.
HS2 said the extra work would not affect or conflict with Higginss current role at HS2.