Question to the Department for Environment, Food and Rural Affairs:

To ask Her Majesty's Government whether the construction of the Thames Tideway Tunnel is (1) on time, and (2) on budget.

The Thames Tideway Tunnel is being financed and built by Bazalgette Tunnel Limited, also known as Tideway. Tideway report quarterly to Government on progress. In their most recent report, covering October to December 2018, Tideway report that construction is on track. The tunnel will be operational by 2023.

Tideway issued a press release on 4 April which outlines recent progress and updates their latest cost estimate. Their revised estimate is £3.361 billion (in 2014/15 prices), which is an increase of £217m on the £3.144 billion baseline set at the start of the project. Tideway estimates that it does not change the estimated £20-25 peak annual cost for Thames Water customers (in 2014/15 prices), as overall costs remain within that range. This level of increase has no impact on the taxpayer.