Thames Water has been hit with a record breaking £1m fine after toxic sewage waste leaked into a canal.
Waste from the Thames Valley treatment works overflowed into the Wendover Arm of the Grand Union Canal in Buckinghamshire over a nine-month period between July 2012 and April 2013.
Poorly performing sewage inlet screens at the plant became blocked with wipes and other non-flushable items leading to debris and sludge being discharged into the canal.
Thames Water pleaded guilty to two charges under the Environment Permitting Regulations 2010.
At St Albans Crown Court Thames Water was fined £1 million, the highest ever penalty for a water company in a prosecution brought by the Environment Agency.
They were also ordered to pay prosecution cots of £18,113 and a victim surcharge of £120.
The court heard how the Environment Agency received complaints from the Canal and Rivers Trust and from the general public about the pollution and sewage debris including panty liners and ear buds was found.
Speaking outside court, a spokesman for Thames Water said:
The 6.7 mile-long Wendover Arm opened in 1799 and was originally designed to supply water to the summit level of the Grand Junction Canal.
It has been unnavigable since 1897 and is currently being reconstructed by charity group the Wendover Arm Trust.