The water companies in the UK with the worst financial performance are South East, Thames, Southern, and SES.

Regulator Ofwat stated that the businesses were under strict observation and had been instructed to patch up any financial gaps.

It follows concerns earlier this year about the future of Thames Water, the biggest supplier in the UK, because of its £14 billion debt load.

Ofwat was criticized at the time for its “complacent” approach to managing the industry.