Maria Eagle, the shadow transport secretary, confirmed in a speech to the Airport Operators Association that Labour has abandoned the route it had proposed when in government for the planned HS2 line between London and Birmingham in favour of an alternative scheme.

Labour now supports a route running past Heathrow and then parallel to the M40 and the existing Chiltern railway line that skirts Princes Risborough, Bicester and Banbury.

The initial plan was drawn up by Lord Adonis, the former transport secretary, two months before last year’s general election. In a speech to the Airport Operators Association, Eagle will admit it was flawed and that it was a “huge mistake” not to connect Heathrow to the route from the start.

Labour’s new proposed route will appeal to many Tories in the Amersham, Great Missenden and Wendover areas who are dismayed by the prospect of a line enabling high speed trains to pass through Conservative heartlands in the Chilterns.

In an attempt to put pressure on Justine Greening, the new transport secretary who is facing opposition over the route from grassroot Tories, Eagle will say that residents in the home counties have been “wrongly insulted as nimbys by Tory ministers”.

The route now proposed by Labour would include a main transport hub at Heathrow, allowing the airport to be directly connected to the High Speed Two (HS2) railway line as early as 2022.  Under the existing plan, Heathrow will be connected to HS2 only by a spur line that is not projected to be completed until 2033.

Greening is already facing a potential battle over the HS2 scheme after Cheryl Gillan, the Welsh secretary, reportedly threatened to resign over the £33 billion project in protest at the route passing through her Buckinghamshire constituency.