Thames Water fined for 'catastrophic incident leading to an avalanche of foul waste'.


Thames Water have 56 days to pay £4,000,000 + £84, 646 costs for the sewage spill that took place at the Green Lane Recreation Ground during 2016, as announced by the Judge at Aylesbury Crown Court this afternoon. see here Hogsmill sewage leak

Although Thames Water pleaded guilty to this offence in 2019, it has taken - 2 years - to appear in the court lists. In addition, Thames Water asked for 4 TIC's (offences to be taken into consideration). See these incidents below and links to the blog posts:

  1. 8th February 2016 - pertains to the pollution of Green Lane Recreation Ground;
  2. 27th January 2018 - spillage of stored sewage sludge
  3. 14-16th October 2018 Sewage-spill-green-lane-recreation.html and linked incident 24.10.18
  4. 25th September 2019 Green-lane-sewage-spill

30 personnel were required to remove 2,500 bags of waste from the Green Lane recreation ground, New Malden; the public amenity remained closed for almost one month (photo above) after the Tunnel Sewer (Worcester Park-Green Lane) Pumping Station failed.

When Storm Imogen was predicted, Thames Water did not perform a due diligence assement of the risks, which should have put the company on a high alert. Such surcharges had ocurred previously at this site, leading to the - removal of the childrens playground - away from the surcharging manhole cover.

When the Tunnel Sewer pumps failed due to a power outtage 46 priority alarms were ignored 

The result: five hours of flooding  and the incident was not reported to the Environment Agency until 9pm, 16 hours later with no mention of the impact on the Hogsmill river. Thames Water operatives reported this as a ' catastrophic pollution incident leading to an avalanche of foul waste, ankle deep in raw sewage'. The sewage erupted so hard and fast that grit and gravel carved a path to the Hogsmill river and 2,500 bags of rag were removed from the playground which partially re-opened on 11.3.16.

It was estimated that 79-80 million litres of sewage entered the Hogsmill river, a chalk stream and Grade 1 Site of Nature Conservation Importance. It transpired that engineers had requested the replacement of 4 pumps, eight months prior to the incident. But a wide range of factors led to the catastrophe such as:

  • Software malfunction turning off  pumps;
  • Flow meter inaccuracies - TW didn't even know how much sewage they were treating; and
  • Reporting failures.


Thames Water has a £2,000,000,000 (billion) turnover, which is £44,000,000 per week.

Thames Water Hogsmill Sewage Works is an unmanned sewage works receiving the waste of 400,00 people, which is about to steadily increase with a new mega-city planned for Norbiton, developer- termed 'East Kingston' and Kingston Town.


Consented Spills

Thames Water are allowed to discharge sewage into our rivers when certain conditions apply and here are some examples of past spills. Modernisation of the works has meant that we no longer have to put up with the gross rag as detailed here but the liquid content is still present during high rainfall events.

Consented spills  

Sewage clean-up July 2016 

September sewage 


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