Thames Tideway Tunnel – Sewer tunnel

More data

Country: United Kingdom
Fund: DIF IV
Project capital cost: GBP 4.2 billion
Investment date: Aug - 2015
Status: Construction


  • The Thames Tideway Tunnel project (TTT) is the largest single asset in the water sector, and will form part of the London (UK) sewer network. The project will comprise a 7.2m diameter tunnel that will run for 25km at depths of 65 meters below the river Thames, with multiple sewage inflow points and will connect with a sewage process works downstream.  The project construction is required to tackle the discharge of untreated sewage into the tidal River Thames and to significantly increase the capacity in the sewerage network servicing Thames Water’s 9 million customers;
  • DIF’s consortium partners are Allianz, INPP and Dalmore;
  • The total project value is £ 4.2 billion, with an expected construction period of 6 years;
  • The project will result in £ 20 - 25 per year being added the water bills of Thames Water’s customers, which is around a third of the original estimate due to the involvement of the private sector, and innovative financing and construction;
  • Construction of the project will be under three main contracts, with BMB JV (JV of BAM Nuttall, Morgan Sindall and Balfour Beatty) selected for the West contract, FLO JV (JV of Ferrovial, Laing O’Rourke Construction) for the Central contract and CVB JV (JV of Costain, Vinci, Bachy) for the East contract;
  • Six banks have provided an innovative debt structure to the project, including Royal Bank of Canada, Lloyds Bank, Credit Agricole, SMBC, BTMU and Santander. Financial close was achieved in August 2015 and project debt has received a rating of Baa1 by Moody’s;
  • Thames Tideway will operate under the UK’s existing water regulatory framework, with bespoke features to reflect the nature of the construction obligations. There will also be a mechanism applied after construction to incentivise cost and time savings, and from 2030 the project will be subject to 5-yearly regulatory reviews.