SIX private water companies across England are facing landmark legal action over allegations of under-reporting pollution incidents and overcharging customers.

Severn Trent Water, Thames Water, United Utilities, Anglian Water, Yorkshire Water and Northumbrian Water could end up forking out more than £800 million in compensation to over 20 million customers if the cases are successful.

Environmental and water consultant Professor Carolyn Roberts, who is being represented by Leigh Day Solicitors, claimed that the firms have broken competition laws by misleading the Environment Agency and regulator Ofwat.