According to the Daily Telegraph on 3 December, Transport secretary Justine Greening will announce early next week that extra money has been found to pay for a 2.4 kilometre-long (1.5 miles) tunnel under the Chiltern Hills beyond Amersham.It would mean that the train line will not scar an area of outstanding natural beauty in the Chilterns, as had been feared and could head off the threatened resignation of Welsh secretary Cheryl Gillan, who had reportedly threatened to quit if HS2 ran through her Chesham and Amersham constituency.

The first six mile section of the track from Euston to Old Oak Common Lane in northwest London is tunnelled before running over-ground to the M25, and then passing through another tunnel. This tunnel surfaces after Amersham for a mile, before entering a shorter tunnel, which ends at South Heath. The new cash will be used to join up the Amersham tunnel with the shorter tunnel.

The new tunnel will mean that a final decision on whether to give the green light to the HS2 project will now be delayed from this month to mid-January. The money has been found from a thorough review of the entire route and reconfiguring some of the deep cuttings and green tunnels further up the line.

Ms Greening had been expected to make a decision whether to go ahead with HS2 before Parliament rises for its Christmas break on December 20. Now however the decision will be made after January 10, when MPs return from their Christmas and New Year break.