7-Oct-2023
Triumph of the Nimbys ?
As the dust settles following the cancellation of Phase 2, attempts are being made to pin the Phase 1 cost overruns on Nimbys in the Chilterns, who forced changes on the scheme (how ?), and even tried to obtain fair market prices for their properties. The Institute for Government explains
Scope changes: the scope of HS2 expanded after its original announcement, with changes to the original plans driving increased cost. For example, during the passage of the hybrid bill to approve the first phase of the line, political pressure from protestors and constituents led MPs to vote to lengthen the tunnel through the Chilterns.
HS2 Ltd. estimate that scope changes accounted for £1bn of the £20–26bn increase between 2017 and 2019.
This might suggest that the Chiltern Tunnel extension was responsible for some significant fraction of £1bn due to scope changes, or even the £26bn overall increase. If only ...
Not us, guv.
At the root of most of the problems with HS2 phase 1 is the hybrid bill process by which it was approved. Until the bill is passed, the promoter has no right of access to conduct ground investigations; the arrogance and insensitivity with which the 'Community Engagement' operations were conducted during the 'consultation' period lead to agreement being frequently withheld. Consequently, the design prepared for approval by parliament was drawn up without adequate investigations, and by engineers who had no intention of building it. It wasn't very good, but the select committee stage did not allow any discussion of whether HS2 should be built, or where.
Most changes to the initial designs were made by the promoter, to remove glaringly obvious faults, e.g.
- Tunnelling into London from Ruislip was needed to avoid closure of the Hanger Lane gyratory system for a year or more
- The Chiltern tunnel was extended from Amersham to Hyde Heath, as the initial design would have created as much spoil as the Channel tunnel.
The extension to South Heath
The only major significant route change in the Chilterns to be forced on HS2 was the further extension of the Chiltern Tunnel to a point just beyond South Heath - previously the end point of a cut and cover tunnel which passed through Sibleys Coppice. This was approved by the HS2 select committee on 21st July 2015, in the face of strong opposition from the bill promoter - to save an additional cost of £75m ! This figure was disputed by the petitioners, who claimed a net saving of £18m. The figures presented to the committee (as part of presentation A1239) are shown below, but there is nothing to suggest that the additional 2.6km extension granted had any significant impact on the £1 billion cost increase referred to by the Institute (and was approved by the committee two years before the increase occurred) -
![](2023/A1239-1.jpg)
The points at issue were the cost of additional bored tunnel, the savings from not excavating the cuttings or cut and cover tunnel, and the proceeds from reselling some property CPO'd by HS2. The incidental saving of parts of 3 ancient woodlands (Mantles, Farthing wood, Sibley's coppice) as not disputed.
The presentation to the select committee was made by REPA (the Residents Environmental Protection Association), who raised in excess of £80,000 for legal and engineering advice; this was not refunded following their partial success.
It might also be noted that the predicted tunnelling rate of 80m/week was one argument used against extending the Chiltern Tunnel to Wendover as this would take to long; the tunnel consequently emerges on top of the Chiltern Hills rather than at the far side in a traditional tunnel like fashion. The tunnelling rate to date is of the order of 110m/week.
Summary
Increases in the actual cost of construction (as opposed to increases due to the revelation of anticipated but concealed costs ) are a result of poor and inflexible route design, the high design speed and the lack of surveying work before the route was chosen. If the Chiltern Nimbys had been given any say in spending £1bn, the tunnel would extend to Wendover.