Lee Tunnel

65m tonnes of CO2 saved

£22m cost savings

Deepest tunnel ever bored under London

The UnPS-designed, seven metre diameter Lee Tunnel runs for 6.9 kilometres from Abbey Mills Pumping Station to Beckton Sewage Treatment Works.

In addition to featuring the world’s largest Steel Fibre Reinforced segmental lining, the project involved three of the largest continuous concrete pours ever undertaken in the UK, for the base slab (5,000m3), shaft lining (11,000m3) and slipformed central wall (7,200m3). This was recognised by Thames Water’s ‘Health and Safety in Planning and Design 2014’ award, and commendation at the IStructE Structural Awards 2014.

We also designed the award-winning Lee Tunnel Pumping Station, one of the largest underground structures of its type in the world and one of the most important strategic infrastructure assets in the UK. By taking a holistic approach to its design and construction methodology, we delivered enhancements in safety and buildability, plus cost and time savings, whilst improving long-term structural durability.

  • Customer: MVB joint venture on behalf of Thames Water
  • Completion: Completed 2015
  • Project value: £635m
    UnPS design commission value £8.1m
  • The tunnel will prevent more than 16 million tonnes of sewage and rainwater overflowing into the River Lee annually, by capturing and transferring it to Beckton.
  • UnPS developed the SlipStress™ and SmartShell™ shaft and tunnel lining methods during this project, enabling the removal of 19,000 tonnes of reinforcing steel whilst greatly enhancing the structures’ durability, and saving £22 million.
  • SlipStress™ won Design Innovation of the Year at the NCE/ITA Tunnelling Awards 2014.