Even in the most promising areas, the presence of a busy main road can stall regeneration.

Daniel Freiman

Canning Town may have realised its potential sooner following the completion of the Jubilee line extension had it not been for the presence of the giant interchange of two A roads. On the other side of town, the A4 carves a canyon between Hammersmith and the banks of the Thames. Barking has similar challenges with the A13. Putting sections of roads underground – ‘flyunders’ – can relieve road congestion and have huge regenerative benefits in the right location.

Within London, this vision is becoming clearer with the current mayor taking a long-term, strategic approach. There is a keen eye on opening up potential for additional development at the surface, for example, to provide housing, offices, mixed leisure and retail uses and new areas of open space. There will be opportunities for developers to work in partnership with Transport for London to bring forward development over or near to subsurface road infrastructure. The mayor has said a significant portion of funding for the flyunders is expected to be generated by the tunnels themselves and the homes they would enable.

Promoting road tunnel projects and above-ground development in London is, however, a complex business. In terms of securing planning consent, key factors include deciding what powers will be needed to construct and operate the scheme, the strategy for land acquisition, environmental impact and dealing with complex interfaces with other infrastructure and development. Finally there is the public and, crucially, political dynamic. 

We had to navigate all these issues and more when working with Thames Water to secure development consent for the 16-mile Thames Tideway Tunnel, a nationally significant infrastructure project (NSIP) under the Planning Act 2008. The NSIP regime may well be applicable to the road tunnel and flyunder schemes proposed by the mayor. The NSIP route is capable of offering a fairly quick examination and decision-making process with certainty of timescales. That certainty is a key consideration for promoters and funders. Of course, equalising speed with robustness is crucial given that any defect might not be obvious until the end of the planning process. Add to this the need to future-proof consents to cope with changing technical, economic and physical environments, and you can see how any route to consent becomes more challenging. 

Political will is key to getting any tunnel off the drawing board and into the ground. Time will tell whether London’s next mayor will embrace these ambitious proposals.

Daniel Freiman (pictured) is a senior associate and Christian Drage is a partner at Berwin Leighton Paisner