Thames Water has been handed a £2 million fine after allowing raw sewage to flow into a river, wiping out a local fish population.

The pollution killed around 150 bullhead fish after flowing into a tributary of the River Thames for at least 24 hours.

Judge Peter Ross branded the incident a "reckless failure" of the company to take sufficient action to prevent a spill.

The court heard Thames Water had ignored more than 1,000 alarms at the west Oxfordshire pumping station where the incident took place.

According to the judge, a culture had been created where employees interpreted a problem with the pump system as a problem with the alarm system.

"It's that failure to integrate the technological advances with human assessment, analysis and response which lies at the heart of the deficiencies that were created in this case,” he said.

"In order to be operated effectively there had to be a proper integration of the technology and human resources, adequate training for the latter and a culture ensures that the exercise of judgment is still undertaken by human beings."

The utilities firm, which has a turnover of £2bn, admitted to breaching regulations with regards to the incident in which sewage had entered a stream near Milton-under-Wychwood in 2015.

In his defence of the company, Kerim Fuad QC said prior to the spill there had not been an incident at the Cotswolds site since 1993.

Extinction rebellion: Climate change protesters block London bridges Show all 25 1 /25 Extinction rebellion: Climate change protesters block London bridges Extinction rebellion: Climate change protesters block London bridges Demonstrators block Westminster Bridge in central London to show anger at government inaction on climate and ecological issues AFP/Getty Extinction rebellion: Climate change protesters block London bridges A pro environment protester is arrested by police on Lambeth bridge in London EPA Extinction rebellion: Climate change protesters block London bridges Organised by Extinction Rebellion, the protest is part of many taking place this weekend to bring attention to political inaction on issues of pollution and climate change Reuters Extinction rebellion: Climate change protesters block London bridges A demonstrator puts tape on her mouth as she takes part in a pro-environment protest blocking Westminster Bridge in central London on November 17, 2018, calling on the British government to take action on climate and ecological issues. - Organized by Extinction Rebellion, the protest is part of many taking place this weekend to call for action on what they describe as a climate and ecological emergency. Extinction Rebellion demands that the UK government reduces to net zero greenhouse gas emissions by 2025 and creates a citizens assembly to oversee changes in environmental policies. (Photo by Tolga AKMEN / AFP)TOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Extinction rebellion: Climate change protesters block London bridges Organised by Extinction Rebellion, the protest is part of many taking place this weekend to bring attention to political inaction on issues of pollution and climate change PA Extinction rebellion: Climate change protesters block London bridges Demonstrators on Blackfriars Bridge PA Extinction rebellion: Climate change protesters block London bridges Police with demonstrators on Blackfriars Bridge PA Extinction rebellion: Climate change protesters block London bridges Demonstrators take part in a pro-environment protest as they block Westminster Bridge in central London on November 17, 2018, calling on the British government to take action on climate and ecological issues. - Organized by Extinction Rebellion, the protest is part of many taking place this weekend to call for action on what they describe as a climate and ecological emergency. Extinction Rebellion demands that the UK government reduces to net zero greenhouse gas emissions by 2025 and creates a citizens assembly to oversee changes in environmental policies. (Photo by Tolga AKMEN / AFP)TOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Extinction rebellion: Climate change protesters block London bridges epa07172610 Pro environment protesters block Westminster bridge in central London, Britain, 17 November 2018. Reports state that the protest organized by Extinction Rebellion group is planning to close five main bridges across the river Thames, seeking to bring attention to political inaction on issues of pollution and climate change. EPA/FACUNDO ARRIZABALAGA FACUNDO ARRIZABALAGA EPA Extinction rebellion: Climate change protesters block London bridges A demonstrator is led away by police on Blackfriars Bridge PA Extinction rebellion: Climate change protesters block London bridges Environmental campaigners from the direct action group Rebellion demonstrate on Westminster Bridge in central London, Britain, November 17, 2018. REUTERS/Peter Nicholls PETER NICHOLLS Reuters Extinction rebellion: Climate change protesters block London bridges Police with demonstrators on Westminster Bridge in London for a protest called by Extinction Rebellion to raise awareness of the dangers posed by climate change. PRESS ASSOCIATION Photo. Picture date: Saturday November 17, 2018. See PA story PROTEST Rebellion. Photo credit should read: John Stillwell/PA Wire John Stillwell PA Extinction rebellion: Climate change protesters block London bridges Environmental campaigners from the direct action group Rebellion demonstrate on Westminster Bridge in central London, Britain, November 17, 2018. REUTERS/Peter Nicholls PETER NICHOLLS Reuters Extinction rebellion: Climate change protesters block London bridges Demonstrators take part in a pro-environment protest as they block Westminster Bridge, near the Houses of Parliament in central London on November 17, 2018, to show anger at government inaction on climate and ecological issues. - Organised by Extinction Rebellion, the protest is part of many taking place this weekend to bring attention to political inaction on issues of pollution and climate change. (Photo by Tolga AKMEN / AFP)TOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Extinction rebellion: Climate change protesters block London bridges Demonstrators take part in a pro-environment protest as they block Westminster Bridge in central London on November 17, 2018, to show anger at government inaction on climate and ecological issues. - Organized by Extinction Rebellion, the protest is part of many taking place this weekend to bring attention to political inaction on issues of pollution and climate change. (Photo by Tolga AKMEN / AFP)TOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Extinction rebellion: Climate change protesters block London bridges Police with demonstrators on Westminster Bridge in London for a protest called by Extinction Rebellion to raise awareness of the dangers posed by climate change. PRESS ASSOCIATION Photo. Picture date: Saturday November 17, 2018. See PA story PROTEST Rebellion. Photo credit should read: John Stillwell/PA Wire John Stillwell PA Extinction rebellion: Climate change protesters block London bridges epa07173093 A pro environment protester infornt of police on Lambeth bridge in London, Britain, 17 November 2018. Reports state that the protest organized by Extinction Rebellion group is planning to close five main bridges across the river Thames, seeking to bring attention to political inaction on issues of pollution and climate change. EPA/FACUNDO ARRIZABALAGA FACUNDO ARRIZABALAGA EPA Extinction rebellion: Climate change protesters block London bridges epa07172601 Pro environment protesters block Westminster bridge in central London, Britain, 17 November 2018. Reports state that the protest organized by Extinction Rebellion group is planning to close five main bridges across the river Thames, seeking to bring attention to political inaction on issues of pollution and climate change. EPA/FACUNDO ARRIZABALAGA FACUNDO ARRIZABALAGA EPA Extinction rebellion: Climate change protesters block London bridges epa07172698 Pro environment protesters hold a placard as they block Westminster bridge in central London, Britain, 17 November 2018. Reports state that the protest organized by Extinction Rebellion group is planning to close five main bridges across the river Thames, seeking to bring attention to political inaction on issues of pollution and climate change. EPA/FACUNDO ARRIZABALAGA FACUNDO ARRIZABALAGA EPA Extinction rebellion: Climate change protesters block London bridges Demonstrators on Westminster Bridge in London for a protest called by Extinction Rebellion to raise awareness of the dangers posed by climate change. PRESS ASSOCIATION Photo. Picture date: Saturday November 17, 2018. See PA story PROTEST Rebellion. Photo credit should read: John Stillwell/PA Wire John Stillwell PA Extinction rebellion: Climate change protesters block London bridges Environmental campaigners from the direct action group Rebellion demonstrate on Westminster Bridge in central London, Britain, November 17, 2018. REUTERS/Peter Nicholls PETER NICHOLLS Reuters Extinction rebellion: Climate change protesters block London bridges epa07172703 Pro environment protesters hold a placard as they block Westminster bridge in central London, Britain, 17 November 2018. Reports state that the protest organized by Extinction Rebellion group is planning to close five main bridges across the river Thames, seeking to bring attention to political inaction on issues of pollution and climate change. EPA/FACUNDO ARRIZABALAGA FACUNDO ARRIZABALAGA EPA Extinction rebellion: Climate change protesters block London bridges Demonstrators take part in a pro-environment protest as they block Westminster Bridge in central London on November 17, 2018, to show anger at government inaction on climate and ecological issues. - Organized by Extinction Rebellion, the protest is part of many taking place this weekend to bring attention to political inaction on issues of pollution and climate change. (Photo by Tolga AKMEN / AFP)TOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Extinction rebellion: Climate change protesters block London bridges epa07172629 Pro environment protester holds a placard as they block Westminster bridge in central London, Britain, 17 November 2018. Reports state that the protest organized by Extinction Rebellion group is planning to close five main bridges across the river Thames, seeking to bring attention to political inaction on issues of pollution and climate change. EPA/FACUNDO ARRIZABALAGA FACUNDO ARRIZABALAGA EPA Extinction rebellion: Climate change protesters block London bridges Environmental campaigners from the direct action group Rebellion demonstrate on Westminster Bridge in central London, Britain, November 17, 2018. REUTERS/Peter Nicholls PETER NICHOLLS Reuters

He also noted Thames Water operated more than 4,700 pumping stations across its range, but Judge Ross branded this detail “irrelevant”.

"Any loss of fish or damage to the environment short or long term is extremely regrettable but the cause of this unfortunate event in many respects remains unknown,” said Mr Fuad.

Judge Ross said pollution risk must be managed at each site, regardless of how many there were.

Mr Fuad told Oxford Crown Court on Friday £40 million had been invested by Thames Water in improving waste water sites, and the company had demonstrated deep regret for the spill.

Support free-thinking journalism and attend Independent events

He also compared the incident to previous convictions for Thames Water, including a record £20m fine imposed at Aylesbury Crown Court in 2017.

Hundreds of fish as well as birds and dragonflies were killed by that spill, in which sewage flowed into nature reserves, bringing with it nappies and other debris.

"Had lessons really been learned and implemented from the events in relation to the two previous convictions then this would not have happened,” he said.

Responding to the ruling, Richard Aylard of Thames Water said: “We take our role in protecting the environment extremely seriously and are really sorry for what happened here in 2015.”

“We have made a series of improvements since this regrettable incident, including bringing in more people, more maintenance, more training and better systems. In the three-and-a half-years since, we have not had a serious incident at any of our 4,700 pumping stations.

“We would like to reassure our customers that we continue to innovate and drive further improved performance right across the business, to help us achieve our ambition of zero pollutions.”

