Construction of the proposed Hamersmith ‘flyunder’ could begin within five years, assuming various planning and financing hurdles are overcome.
“We are about two to three years behind the Silvertown Tunnel, which has an estimated start date of 2017,” said Nick Boyle, transportation and development manager for the London Borough of Hammersmith & Fulham (LBHF).
He was speaking at a briefing on the progress of the flyunder scheme. LBHF is proposing construction of a tunnel to replace the Hammersmith Flyover, which was closed for emergency repairs in 2011.
A Halcrow-produced feasibility study published in March suggested three options: a 15m-deep, cut-and-cover tunnel, costing £218M, and running along the 1.6km route of the existing flyover; a longer, more expensive twin-bore tunnel, costing up to £1.7bn and stretching for 4.1km between Chiswick and Earl’s Court; and another twin-bore tunnel, 3.5km long, which would emerge at North End Road.
The report found no subterranean ‘showstoppers’, and the twin-bore tunnel would run through London clay at a depth of upto 25m.
Since the study was published, the Conservatives have been replaced as majority party in LBHF by Labour. However, Boyle said the new administration was supporting the flyunder plans. Councillor
Andrew Jones, cabinet member for economic development and regeneration, is now responsible for progressing the project.
The scheme would be part-financed by release of land from demolition of the Hammersmith flyover, which could yield up to £1bn from developers.
The LBHF team has presented the proposal to Transport for London (TfL) and the Mayor of London, Boris Johnson, who described it as a “brilliant” idea, but said its viability may depend on the development potential of the land released.
Boyle said options were being examined for integrating the project with other TfL schemes, including: the Better Junctions programme, which could see the Hammersmith Gyratory remodelled into a pedestrian-friendly ‘peninsula’ in similar fashion to the Elephant & Castle roundabout; and the Inner Ring Road mooted by TfL’s Roads Task Force.
The flyunder team will now review further options for relocating strategic traffic, freeing up pinch points on the network, and release of space for other land uses. Its next update on the scheme is due in March 2015.
The existing Hammersmith Flyover is being repaired by TfL at a cost of £60M.