The Parliamentary Under-Secretary of State for Environment, Food and Rural Affairs (Richard Benyon)

This figure is expected to increase. Recent Thames Water work has shown that the system is operating closer to its maximum capacity than previously recognised and, with population growth, increasing urbanisation and climate change, it is estimated that in 10 to 20 years time sewage will be overflowing into the Thames even when there is little rain.

Since the 22nd March 2007 statement by the then Minister for Climate Change and the Environment and Member for Dudley, South (Ian Pearson), on the need to improve the water quality in the Thames by upgrading the sewerage infrastructure, Thames Water have started work on building a tunnel (known as the Lee tunnel) from Abbey Mills pumping station to an upgraded Beckton sewage treatment works at a total cost of around £0.8 billion. When complete these works should reduce the total volume of sewage overflows into the tidal Thames by around two thirds. However significant volumes of raw sewage will still continue to enter the Thames at times of heavy rainfall particularly in the higher reaches of the tidal Thames from Hammersmith through central London which will get less benefit from the Lee tunnel.

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