HS2 may include a tunnel under the Chilterns

Transport Secretary Justine Greening has demanded more of the high speed rail line be buried under ground. The minister will this week announce a delay in the final decision for the £32bn, 100-mile project, after asking officials to examine ways of mitigating the impact of the HS2 line on the countryside.

A plan to enclose more cuttings with displaced soil could free up £500m for a tunnel near Amersham to minimise impact on the Chiltern Hills landscape. The project is aimed at increasing capacity on Britain's railways and cutting journey times to the Midlands and north of England. Several Tory MPs, including Welsh Secretary Cheryl Gillan, oppose the plan.