WATER companies should be investigated following reports that they may have illegally dumped sewage on dry days, Labour demanded today.

Companies are only supposed to spill after heavy rain to prevent the system from backing up and flooding homes and businesses with raw sewage.

But an investigation from the BBC, which looked at data from Wessex, Thames and Southern Water, suggested these companies were discharging sewage on some of the hottest and driest days of 2022.