Holden joined Crossrail from London & Continental Railways in April 2009, having overseen the successful delivery of the new High Speed 1 railway between St Pancras International and the Channel Tunnel.

After almost two years at Crossrail, he will be leaving later this year to explore new opportunities – believed to be a string of non-executive director roles.

Terry Morgan, Crossrail Chairman, said: “Rob came on board soon after we secured Royal Assent to the Crossrail Act.

“He has successfully taken Crossrail from the drawing board, through the detailed design process, above all through very effective and successful negotiation with Government to secure a green light for Crossrail under the Comprehensive Spending Review, to the award of the main tunnel contracts late last year and the start of full construction.

“In the process he has achieved savings of over £1 billion in the programme, whilst preserving the project’s original scope.

“We regret his decision to step down but respect it. He leaves the project in great shape and we are on firm foundations to maintain our momentum to deliver this critically important project for the UK, on time and within budget.”

Holden said: “I am proud to have led the Crossrail team over the past two years, and to have seen the project receive an unequivocal green light from Government in the recent Comprehensive Spending Review.

“With the project moving into its construction phase, Crossrail needs a Chief Executive who can commit to lead right through to opening in 2018.

“I leave Crossrail confident that, with its funding firmly in place, a robust delivery plan, clear governance and a strong delivery team, Crossrail is now well set to move forward to a successful launch.”

The exact date of Holden’s departure has yet to be finalised and Crossrail has begun the process of identifying a suitable successor.