The Thames Tideway Tunnel

• Much of London is served by a combined sewerage system, collecting sewage from homes as well as rainwater run-off from roads, roofs and pavements,
• 1858 - during periods of heavy rain, the Victorian drainage system discharges raw sewage into the River Thames, killing aquatic life and threatening public health
• 2013 - 55 million tonnes of raw sewage was washed into the river.

  Response - under construction to upgrade drainage system e.g. a 25km long tunnel to transport sewage to be completed in 2025