Southern Water has been fined £90 million by the Environment Agency (EA) after pleading guilty to 6,971 unpermitted sewage discharges.
The offences relate to incidents between 2010 and 2015 in Kent, Hampshire and Sussex in the largest criminal case brought by the EA.
The court was told Southern deliberately presented a misleading picture of compliance to the EA, hindering proper regulation of the company.
Environment minister Rebecca Pow called the case “shocking and wholly unacceptable”.
She said: “This fine, the largest ever imposed on a water company, is absolutely appropriate and welcomed. It will rightly be paid solely from the company’s operating profits, rather than customer bills.
“I have spoken directly to the industry about taking their environmental responsibilities seriously, protecting rivers, lakes, streams and the wildlife that rely on them. Some companies are making welcome strides, but we still need to see significant improvements from others.”
The Agency said the offences were caused by deliberate failings, causing major harm to protected areas, conservation sites and oyster beds.
The sentencing judge Justice Johnson said: “Each of the 51 offences seen in isolation shows a shocking and wholesale disregard for the environment, for the precious and delicate ecosytems along the North Kent and Solent coastlines, for human health, and for the fisheries and other legitimate businesses that depend on the vitality of the coastal waters.
“Each offence does not stand in isolation. It is necessary to sentence the company for the totality of the offences to which it has pleaded guilty. But even that does not reflect the defendant’s criminality. That is because the offences are aggravated by its previous persistent pollution of the environment over very many years.”
Chief executive Ian McAulay said he was “deeply sorry” for the “completely unacceptable” incidents.
“We have heard what the judge has said today and will reflect closely on the sentence and his remarks. He has rightly put the environment front and centre which is what matters to all of us.”
McAulay said the company has changed the way it operates to be fully transparent and operate in the right way.
“We continue to transform across the areas of risk and compliance, measurement and self-reporting. We have made much progress and are continuing to invest to protect the environment and deliver our services safely and at a fair price for our customers,” McAulay said.
He added the fine would not impact customers’ bills or reduce its investment in transforming because shareholders will bear the cost of the fine.
Southern was fined £126 million by Ofwat for regulatory breaches relating to the same offences in 2019.
Emma Clancy, chief executive of CCW, said: “The scale of this fine should send a very clear message that harm to the environment will not be tolerated – but it would have a far greater impact if the money was reinvested in the region where the damage was caused.
“We recognise that Southern Water has already taken steps to ensure these past offences and failures are never repeated and we hope this marks a turning point for the company so it can repair customers’ fractured trust.”