UK transport secretary Heidi Alexander will order HS2 management to explore reducing train speeds from 360km/h to 320km/h to cut project costs. The directive forces CEO Mark Wild to delay his expected March "reset" announcement until May, when he will present revised estimates showing the budget exceeding £100bn and completion pushed past 2037.

Slower speeds would eliminate the need to send trains to China for testing on existing high-speed tracks or wait for a UK test track to be built. The government believes this modification could save billions in construction costs and years off the delivery timeline. HS2 management is already renegotiating civil engineering contracts with companies including Balfour Beatty, Vinci and Strabag.

The project's cost has ballooned from an original £80bn estimate when launched in 2010. The Conservative government has criticized the previous administration for creating a "gold-plated" project that is "needlessly over-specced." Alexander has accused the Tories of wasting £2bn on preliminary work for the now-cancelled northern leg and "cost plus" contracts lacking appropriate controls.