WATER giant Thames Water has been fined £2 million after a ‘reckless failure’ saw the firm pour sewage into an Oxfordshire brook killing more than a hundred fish.

Judge Peter Ross said yesterday that the company had not learned the lessons from the past after it was fined a record £20m last year for a similar offence and a quarter of a million pounds in 2014.

The water firm - the UK's largest - had already admitted discharging untreated sewage from the Bruern Road Sewage Pumping Station at Milton-under-Wychwood on or before August 9 2015.

Oxford Crown Court heard at a sentencing hearing yesterday how the company had caused the sewage to go into a 50m stretch of the Idbury Brook in the Cotswolds, West Oxfordshire killing 146 Bullhead fish.

The court heard that ahead of the incident a series of alarms had been misinterpreted with the company 'blithely unaware' that anything was wrong with the plant.

This led to a 'complete failure' of the pumping station and sewage seeping out into the brook before local residents and the Environment Agency reported dead fish in the river to Thames Water and a clean-up operation was launched.

Handing out his sentence for the breach of environmental regulations Judge Ross said that it was 'reckless failure' and a lack of learning lessons from the past that led to the incident.

He said: "A reckless failure by the organisation to put in place and ensure such systems as could reasonably be expected in all the circumstances to avoid commission of the offence.

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

The court also heard that Thames Water operated more than 4,780 pumping stations across the region and that there had not been any other incidents at the Milton-under-Wychwood station since 1993.

The Judge said that the fact the water firm was responsible for such a large estate was irrelevant to the failings of the company in managing that site.

He blamed the incident on a 'failure to integrate the technological advances with human assessment, analysis and response'.

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 which ensures that the exercise of judgment is still undertaken by human beings."

Better management and training as well as the establishment of a proper culture could have prevented the incident, the court heard, although Judge Ross acknowledged that improvements had since been made.

In mitigation at the hearing, defence barrister for Thames Water Kerim Fuad QC said that the company was sorry for what it had done.

He said: “Thames Water has expressed remorse and deep regret from the outset and entered a guilty plea almost a year ago in January this year.

“They have always and continue to take their responsibilities to the local environment extremely seriously.”

He added that the firm had the largest investment programme out of any other water company with a £5 billion project set for the period 2015-20.

Speaking after the verdict had been handed down lead investigator at the Environment Agency Robert Davis called the incident 'foreseeable and avoidable.'

He said: "Thames Water didn’t recognise the increased risk to the environment, ignoring or failing to respond adequately to more than 1,000 alarms.

“These streams are normally a haven for kingfishers, grey herons, brown trout and other fish and invertebrates. Sewage poured into the water for 24 hours, having a terrible impact, killing fish and other water life.

“We hope this prosecution sends a loud and clear message that the Environment Agency will not accept poor operation, management and maintenance of sewage pumping stations.

"Where we have evidence of offending and serious pollution incidents like here, we will take appropriate action to bring polluters to justice."

The company has an annual turnover of some £2 billion with weekly profits of £2 million.

Thames Water was fined £2 million and ordered to pay costs to the Environment Agency of £79,991.57.

Judge Ross said that if the company agreed to donate to three environmental charities the fine would be reduced by £200,000.

Richard Aylard, External Affairs and Sustainability Director, 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 re-assure 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.”