 In March 2010, the Government announced the route of HS2, the proposed high-speed railway from London to Birmingham.The line would cross the Colne Valley and the M25 motorway on a viaduct, and then through a tunnel under the Chiltern Hills to emerge near South Heath, northwest of Amersham.The route runs roughly parallel to the A413 and the London to Aylesbury Line, A campaign of opposition is co-ordinated by a protest group, Amersham Action Group, which with other protest groups is part of the HS2 Action Alliance.