Exclusive: Major donor questioning ‘ability to continue support’ for party amid doubt over Birmingham to Manchester leg

A prominent Conservative donor has threatened to stop supporting the party if Rishi Sunak scraps the Birmingham to Manchester leg of HS2, as ministers consider pulling the plug on the multibillion-pound project.

Fears that phase 2 of the high-speed rail line could be junked were compounded on Sunday when Grant Shapps, the defence secretary, said it would be “crazy” not to review the plan in light of spiralling costs.