A water company faces paying a multi-million pound record fine after polluting the River Thames with more than a billion litres of raw sewage, a judge has warned.
Thames Water pumped 1.4 billion litres of unfiltered human waste into the water in 2013 and 2014.
At a sentencing hearing at Aylesbury Crown Court, Judge Francis Sheridan said the seepage in Oxfordshire and Buckinghamshire had destroyed local angling and fishing businesses and left farmers with sick animals.
The overflow in September 2013 saw effluent pass into Barkham Brook, which ultimately runs into the Thames, the court heard.
He told the court that the record fine paid by the water company for pollution was £1 million paid in January 2016.
Judge Sheridan added: "The fine in this case is certainly in excess of that."
He added: "I have to make the fine sufficiently large that they (Thames Water) get the message.
"Alarms going off for days on end, certainly for more than 24 hours.
"The anglers are put out of business, the fishermen are put out of business, the farmers' cattle are poisoned by the water.”
Thames Water admitted environmental charges at an earlier hearing over discharges from sewage treatment works in Aylesbury, Didcot, Henley and Little Marlow, and a pumping station at Littlemore.
Judge Sheridan gave the company credit for paying compensation to people affected by the discharges.
They include a fisherman who was out of business for four years and an "ex gratia" payment to a young man who caught a debilitating stomach bug while on a sailing course, the court heard.
Richard Matthews QC, for Thames Water, likened the firm's maintenance responsibilities to "trying to service a motor car while it is still running" and said it had since spent millions of pounds in upgrading the affected sites.
He added: "The £2 million per day profit, that hasn't been returned (to shareholders).
"One point four billion pounds has been invested in infrastructure and the shareholders are pension funds, by and large.
"They don't need a message about taking this seriously. That message comes from the mouth of the chief executive who is sitting in court.”
Speaking outside court, Mr Robertson said the company was "extremely sorry" for what had happened.
On Friday, the firm pleaded guilty to an additional charge of breaching environmental laws over a discharge from the unmanned sewage treatment plant at Arborfield in Berkshire.
The company is due to be sentenced next week.