A record number of storm drains overflowed with sewage last year in England, official statistics showed on Wednesday, angering campaigners wanting cleaner rivers and seas.

The Environment Agency said there were 464,056 reported sewage spills in 2023 -- up 54 percent from 301,091 the previous year and the highest since current data began being collected in 2016.

In total, there were 3.61 million hours of spills of untreated wastewater -- more than double the amount in the 2022, it added.

Environmentalists have increasingly voiced outrage at the rise in pollution on the UK's beaches and waterways, and have pointed the finger at privatised water companies.

"The scale of the discharges by water companies is a final indictment of a failing industry," said James Wallace, chief executive of campaign group River Action, calling for regulatory reform.

"Rather than investing in future-proofing their infrastructure, fixing leaky pipes, upgrading wastewater treatment plants, these international businesses have plundered our most precious natural resource -- fresh water."

During heavy rainfall, water companies have been allowed to dump untreated wastewater into rivers and the sea to prevent sewers from becoming clogged and flowing back into buildings.

In February, a report by the Rivers Trust charity found that no stretches of river in England were classed as being in "good" overall health.

Leading causes of poor water quality were pollution from fertiliser or livestock and the discharge of sewage, the study found.

Industry body Water UK has said it would triple investment to £10 billion ($12.6 billion) between 2025 and 2030 to cut sewage spills by 40 percent.

River Action took the Environment Agency to court last month over the condition of the River Wye, which is one of Britain's most important waterways.

It claims the agency is allowing the agricultural sector to release highly damaging levels of nutrients from chicken manure into the river, on the border between England and Wales.

Earlier this year, environmental campaigners met in Brighton on England's south coast to call for an end to the dumping of sewage at the town's popular Southwick swimming spot.

In 2022 the Environment Agency found that sewage was dumped into waters near England's most famous beaches for nearly 8,500 hours in 2022, with Brighton beach one of the worst hit.

On Windermere, in the Lake District national park in northwest England, campaigners estimated that over 8,787 hours of untreated sewage was discharged from the seven sites that feed into the lake in 2023.

Thames Water, the nation's biggest supplier, was fined £3.3 million in 2023 for polluting rivers.