The joint venture has been up against two rival heavyweight consortia of leading engineering consultants – Bechtel/Jacobs/Idom Merebrook, and Parsons Brinckerhoff/Ramboll UK – for the key role on the project.

The task of advising on engineering delivery over a 10-year contract period has been budgeted at £250m-£350m.

HS2’s chosen partner will help to manage and co-ordinate design and support management of the major ECI contract programme for civils work packages worth up to £500m.

The Enquirer understands that HS2 is preparing to make an official announcement imminently on its preferred partner.

The appointment would be another coup for CH2M Hill, which picked up a £70m contract on the project back in 2012 to act development partner, assisting HS2 in the engineering, design and environmental work on the proposed line from London to Birmingham.

CH2M Hill acquired Halcrow four years ago, which worked on HS1 and Crossrail. The US company has previously delivered the construction for the 2012 London Olympics as the Olympic Delivery Authority’s delivery partner, as well as programme managing the London Tideway Tunnel and Crossrail.