Plus: hospital admissions for diseases transmitted by water-borne infections rose 57 per cent between 2010 and 2022. 

Adam Vaughan www.thetimes.co.uk

A third of Thames Water’s sewage monitors do not work properly, analysis of official figures has revealed.

The new data comes on a torrid week for the UK’s biggest water company, after shareholders refused to inject £500 million into the heavily indebted business on Thursday, leaving it scrambling for funding and raising fears of the government having to put it into special administration.

Thames Water’s contribution to the state of the country’s rivers also came to the fore this week after new data showed a record number of sewage spills nationally last year after wet weather. The company had the biggest relative increase in raw sewage spills, which soared 112 per cent to almost 17,000 in 2023.

Yet even that number is likely to be an underestimate, according to an analysis of Environment Agency data by the Liberal Democrats. Across England, about 2,200 of the 14,500 monitors on storm overflows which discharge sewage into rivers and seas are not working properly.

Faults can mean monitors not operating for more than 90 per cent of the time, as required by regulations, or problems owing to installation or design issues. Across the industry in England, an average of 15 per cent of monitors are faulty. However, that jumps to 33 per cent at Thames Water, making it the worst company in the sector.

The high figure will also impact the reliability of a real-time spills map published by the company, which still remains the only firm to offer such information on dumping in rivers.

After Thames, the worst companies for faulty sensors were Southern Water and Yorkshire Water, both on about 18.5 per cent. The lowest share was at 4.4 per cent at Wessex Water.

One Southern Water monitor for the Solent was faulty throughout 2022 and only worked for 30 per cent of last year. One Northumbrian Water monitor at Brancepeth, Co Durham, has been recorded as broken for two years.

The government and the water industry have repeatedly boasted about how comprehensively sewage spills are surveyed, after monitoring 100 per cent of outlets at the legal deadline last December.

However, the reliability issues have led the Lib Dems to accuse water firms of a cover-up. “Water companies could be complicit in an environmental cover-up,” said Tim Farron, the Lib Dem environment spokesman. “Why on earth would a firm install these monitors if they don’t even work? The scale of the sewage scandal could be even larger than originally feared.”

A Thames Water spokesman said: “Taking action to improve the health of rivers is a key focus for us and we want to lead the way with our transparent approach to data. We have experienced higher than average long-term rainfall across London and the Thames Valley with groundwater levels exceptionally high for the time of the year.”

A Water UK spokesman said: “Due in part to their operating outdoors and in all weather conditions, some monitors will occasionally be temporarily out of action while maintenance is underway. This has improved and the regulator has taken tough new powers to ensure the highest standards.”

The analysis came as Labour highlighted NHS data showing hospital admissions for diseases transmitted by water-borne infections rose 57 per cent between 2010 and 2022. Counting 15 water-borne diseases, the number of admissions increased from 2,085 people to 3,286. The biggest single cause was Salmonella enteritis, which can be caused by eating contaminated food or drinking contaminated water. Labour claimed the increase showed “the horrific impact of the Tory sewage crisis”.