A local campaign group fighting the Silvertown Tunnel has raised concerns over due diligence and the background business case.
The Stop Silvertown campaign, which has garnered support from the Green Party and London councillors, has been steadily building its profile after Transport for London (TfL) awarded the contract for the £1bn project recently.
An FOI request sent by the campaigners revealed that despite assurances from the mayor's team that all alternative options to the tunnel were considered there seems to have been a lack of in-depth analysis of the single bore option.
TfL has sought to shrug off the accusations of misleading the public after deputy mayor Heidi Alexander wrote to campaigners stating: 'The case for the scheme also includes consideration of a single bore option with tidal flow.
'This option was ruled out due to substantial safety, operational and engineering challenges. While it is not explicitly referenced in the case for the scheme, a key reason for ruling out this option was that a single bore would need to be large enough to accomodate an emergency services access route and this is not feasible due to restrictied land availablity on both sides of the river.'
Ms Alexander also highlighted that TfL's conclusions were endorsed by the Development Consent Order Panel and the secretary of state, who in granting consent agreed with the panel that 'there has been sufficient assessment of alternatives'.
However, TfLs internal emails obtained by FOI suggest a discrepancy.
Emails sent to David Rowe, head of Silvertown Tunnel Sponsorship at TfL, noted: 'Single bore bidirectional can be very robustly rejected on safety grounds ie not feasible.
- 'Single bore one direction was considered for Blackwall and not considered feasible or operatioanlly desirable.
- 'But single bore silvertown operated tidally we haven't covered in depth in the exam.'
- A follow up email said: 'I hope the rather brief response doesn't turn out to trip us up - to be quite honest I'm slightly regretting the 'all feasible options' line...'
A TfL spokesperson said: 'A single bore option was actively considered in the design process early on. It is important to recognise that tunnels are safety critical environments where the impact of collisions and fires pose even greater risk to road users. The confined space within tunnels can make evacuation and emergency services access much more difficult.
'Consequently, a significantly larger single bore tunnel would be required to enable the emergency services to access it and safely evacuate. However, due to the limited land and physical constraints on either side of the river, there is insufficient space for a such a design. Due to these reasons and wider operational and safety concerns associated with tidal operation, a single bore tunnel was ruled out.
'Our conclusion was endorsed by the DCO Panel and by the secretary of state, who in granting consent confirmed: ‘The Secretary of State notes the options appraised and alternatives canvassed… and he agrees with the Panel that there has been sufficient assessment of alternatives’.'
The Stop Silvertown campaign also noted that the business case rests on a charge for the tunnel, which could be reduced at any future mayor's discretion after consultation with organisations representative of regular tunnel users - who might well be supportive of lowerng the charge.
If future tunnel charges were lowered this could also result in induced traffic demand in the area, creating more congestion.
The Stop Silvertown campaign said: 'All the congestion and air quality forecasts for the Silvertown Tunnel project are an elaborate fiction - because they're all based on the pretence that future Mayors will set exactly the level of toll that this mayor wants them to set.'
A TfL spokesman highlighted that the DCO states clearly that the tunnel has to be subject to a user charge – so there is no option to not to have a user charge.
London mayor's are often tempted to promise fare and toll reductions and freezes, however they often do not live up to these promises such is the pressure on TfL's budget. Mayor Khan is a noticeable exception to this and has run into funding issues as a result.