Thames Water has selected contractors for the three tunnel sections of the £4.2bn Thames Tideway Tunnel in the UK.

A joint venture (JV) of BAM Nuttall, Morgan Sindall and Balfour Beatty has been selected to deliver the west section of the tunnel worth £416m.

The central section has been awarded to a JV of of Ferrovial Agroman UK and Laing O’Rourke Construction.

A JV of Vinci Construction Grands Projets and Bachy Soletanche has been awarded the £605m contract for the East works package.

Amey has secured the system integration contract. The company will be responsible for delivering process control, communication equipment and software systems for operation, maintenance and reporting across the Thames Tideway Tunnel system.

Bazalgette Tunnel, a new special-purpose firm appointed to take the project forward, secured its licence from Ofwat as a new regulated utilities business, separate from Thames Water.

The 25km tunnel will run from Acton in the west of London through to Abbey Mills in the east. The construction program is due to run from 2016 to 2023.

The Thames Tideway Tunnel project is expected to stop the flow from the 34 ‘combined sewer overflows’ (CSOs) identified by the Environment Agency as the most polluting. It is estimated to avoid an average 20 million tons each year of untreated sewage discharging into the tidal River Thames in London.

The Thames Tideway Tunnel will link up with the Lee Tunnel, which was built by Thames Water to take wastewater otherwise destined for the river to Beckton sewage works, East London, from early next year.