HS2 construction contracts priced at £19.5bn have already cost £26bn despite being 'just over halfway done', according to HS2 Ltd's chief executive, Mark Wild.
Contracts were rushed in 2020 without balancing risks, leading to cost escalations.
A 'reset' of construction is underway, including reshaping staff, budget adjustments, and contract renegotiations planned for autumn.
HS2 trains with a speed of 225 mph might start running at lower speeds to expedite testing, aiming for services sooner.