The scale of water companies illegally discharging sewage is 10 times greater than the Environment Agency (EA) estimates, MPs have been told.

Peter Hammond, professor of Computational Biology, University College London, said his work analysing sewage treatment works found in 2020 alone 160 breaches of permits granted by the watchdog to allow sewage discharges.

The EA has only prosecuted 174 cases of illegal discharges in the last 10 years, he said on Wednesday.