On 8 August, Bicester Magistrates' Court fined the plant baker £3,000 and ordered it to pay over £5,000 in costs, in a case brought by the Environment Agency.
The court heard that, on 27 September, 2005, Environment Agency Officers were asked to investigate the river at Spiceball Park in Banbury after several reports of dead fish and oil pollution.
The Environment Agency said in a statement, that its officers saw a 70-metre long oily sheen on the river, with a six-metre long blueish green cloudy discharge coming from a surface water outfall at the park. There were up to 20 large dead fish in the river.
Investigations into the cause of the pollution led officers to the Fine Lady Bakeries site where an inspection of the private and public surface water drains was carried out.
Joe Street, MD of Fine Lady Bakeries, said: "We're very sorry if we caused any distress to the fish and we have subsequently put measures in place to stop it happening again." He said he felt the outcome was fair.
Environment Agency officers had previously visited the company on two occasions. According to the agency, officers had highlighted their concerns and made recommendations.
Investigating officer David Headon said that if the bakery had followed these recommendations, then this incident may have been avoided. "This was a disappointing fine against a substantial company," he added.