Thames Water, which supplies homes and business throughout London and surrounding areas, pleaded guilty to pumping millions of litres of undiluted sewage into rivers near the capital’s Gatwick Airport in 2017, killing wildlife.

The fine, handed down at Lewes crown court, southern England, comes shortly after the UK’s privatised water companies pledged to make massive investments to stop raw sewage being pumped into waterways.

Campaigners have expressed outrage that the billions of pounds recently promised to upgrade infrastructure would be passed on to consumers already struggling with higher bills under a cost-of-living crisis fuelled by elevated inflation.

Reports said water bills could surge 40% by 2030 to fund the works amid mounting concerns over water quality and laxer environmental protections post-Brexit.

Thames Water, meanwhile, could reportedly come under temporary renationalisation as it drowns in debt.