Mack, who stars in the BBC comedy Not Going Out, said: “It’s not just about Windermere. Windermere is obviously England’s biggest, most famous lake.
“If the biggest lake is struggling with it, what are other smaller lakes and waterways having to handle?”
Since water companies were privatised in 1989, a total of £72 billion has been paid to shareholders by the sector, according to analysis carried out by Prof Peter Hammond, an economics specialist at the University of Warwick and first reported in the Financial Times.
He examined data by Ofwat, the water services regulator, and the Environment Agency, with campaign group Windrush Against Sewage Pollution using environmental freedom of information requests.
Friends of the Lake District, which has campaigned since 1934 to protect the landscapes of Cumbria, has called for the end of all sewage discharges into the lakes.
There were 246 days in 2022 when sewage was discharged by United Utilities from storm overflows into Windermere lakes, according to Environment Agency data.