Water bosses who allow the most serious sewage leaks should be sent to prison, Labour will say this week.
The party wants to introduce tougher penalties to prevent raw sewage overflowing into rivers and the sea after more than 100 beaches were polluted this summer.
In a speech on Tuesday, Jim McMahon, Labour’s shadow environment secretary, will call for a new target to reduce overflows by 90 per cent by 2030 and new powers for the Environment Agency to enforce existing rules.
In the most serious cases, directors who preside over sewage leaks from unlicensed pipes should be sent to prison, he will say.
He will also call for water companies to be fined automatically if they release sewage into rivers, by installing new monitoring stations they will have to pay to install.
Labour says any fines could be used for long-term investment in Britain’s water infrastructure, but would not lead to higher bills for consumers because of regulations that prevent them rising without consent from Ofwat, the water watchdog.
The call comes after the Environment Agency backed custodial sentences for water bosses in the most egregious cases, such as after repeated interventions from the regulator are ignored.
Labour sources are frustrated that water companies often face little retribution from the regulators for water pollution, while private individuals who fly-tip or break environmental protection laws face criminal prosecution.
They also point to the lost revenue of seaside businesses that do not see any passing trade because beaches are too polluted to visit.
This newspaper has campaigned for greater action on overflows after an investigation by The Telegraph revealed water companies were releasing sewage into rivers 1,000 times a day.
Boris Johnson faced a major rebellion on the issue last year after 22 Conservative MPs voted against the Government over measures to require water companies to take more steps to prevent sewage dumping.
Ministers argued that the measures would have cost billions in infrastructure upgrades that would have led to higher bills for consumers.
The issue re-emerged this summer when beaches across the country were closed to swimmers over concerns about the quantity of sewage in the water.
The leaks are caused by wastewater and rainwater pipes overflowing through storm drains into rivers when heavy rain overwhelms the Victorian infrastructure.
‘Breathe life back into our countryside’
Last year, Southern Water was fined a record £90 million after pleading guilty to 6,971 unpermitted sewage discharges.
Canterbury Crown Court was told the company had deliberately misled the Environment Agency over the scale of the discharges over a five-year period.
Ian McAulay, Southern Water’s chief executive, pocketed more than £550,000 in bonuses on top of his £1 million salary last year and is retiring at the end of 2022.
In his speech on Tuesday, Mr McMahon will draw attention to Liz Truss’s own tenure as environment secretary between 2014 and 2016.
“[Ms Truss] signed off £24 million pounds of funding cuts for environmental protection, including surveillance of water companies to prevent sewage dumping,” he will say.
“Every one of those sewage spills goes right to her door and their plan sees it continuing until at least 2035.
“It’s not enough to halt the surge of pollution. Labour’s ambition will breathe life back into our countryside and coastal communities - areas long abandoned by the Tories.”