The contractors today confirmed they have signed the contract well below Crossrail’s own £250m cost estimate for the first mainline London station to be awarded.

Crossrail flagged up big savings on the Paddington job two weeks ago when it revealed it planned to sign a contract with the joint venture, subject to a 10-day standstill period.

Andy Mitchell, Crossrail Programme Director said: “Crossrail has reached a further important milestone with the award of the first main construction contract for the central London stations.

“The tendering process for the six stations has generated a huge amount of interest from the construction industry with very competitive bids received for the Paddington contract.”

Crossrail has worked hard to engineer savings on the £14.8bn job, but the £100m discount from the original station price has surpassed many industry expectations.

Andrew Wyllie, chief executive of Costain, said: “We are delighted to have secured our fourth Crossrail contract, reflecting our ability to consistently deliver valuable solutions in the rail sector utilising our broad range of capabilities and depth of expertise.

“We look forward to working with Crossrail to deliver this landmark station and to playing our part in enhancing London’s transport infrastructure.”

To complete the project, the joint team intends to draw heavily upon key in-house skills covering piling and foundations, and mechanical and electrical installations.

Work will begin immediately and is scheduled for completion in 2018.

The new Crossrail station in Paddington has been designed to maximise the station’s space while preserving the historic features of the main line station.

The station will take the form of a 260m long, 25m wide and 23m deep underground box located directly under Departures Road and Eastbourne Terrace.