The $US 1.4bn design and build contract was awarded to a consortium comprising Korea's Samsung C&T (50%), Spanish contractor Obrascon Huarte Lain (OHL) (30%), and Qatar Building Company (20%) in May 2013 and encompasses work on the major Msheireb and Education City stations.

However, in a statement to the London Stock Exchange, OHL said that it had received notification of the contract's termination within the next 14 days, which cited "non-compliance of certain contractual obligations."

Qatar Rail subsequently confirmed the termination in a statement and that it had appointed Consolidated Contractors Group to take over the project. QR argued that its decision was taken on "solid contractual grounds."

"Work will continue on the Major Stations project sites as planned, and discussions are underway with subcontractors to ensure continuity," the spokesman said.

OHL said that before the contract was terminated, the consortium had presented QR with several points of dispute, which, under the terms of the contract, should not have led to termination but negotiation of formal arbitration. It argues that the reasons given for the termination "lack any legitimate grounds." Work on the contract was due to be completed by June 30 2018 and OHL says its work outstanding on the project amounted to €247.7m in December 2015.

Msheireb is the central station on the metro network, linking the three lines under construction in the project's first phase, which will total 86km and 38 stations. Education City is the starting point for the Green Line, and was due to be the connection with Qatar's long-distance rail network, although it appears that QR has changed the scope of this project to no longer include a stop at Education City.