Swimmers who have suffered illness as a result of sewage in bathing spots in England and Wales should be given compensation, the Liberal Democrats have said.

The party has tabled an amendment to the Government’s Victims and Prisoners Bill which it says would help people who become unwell from contaminated waterways to get payouts.

It cited official statistics released on Friday which found a sharp rise in the number of designated bathing spots rated as “poor quality”.

The Bill comes before Parliament on Monday.

The Lib Dems said their amendment would permit anyone who has suffered illness as a direct result of criminal conduct in relation to sewage to claim compensation.

It would require the Government to establish a compensation scheme and make provision in relation to the medical evidence required to support claims, the party said.

The Lib Dems have put sewage at the heart of their efforts to flip traditionally Tory seats in so-called “blue-wall” areas across southern England ahead of a general election expected next year.

The party’s spokesman on the environment, Tim Farron MP, said: “Conservative ministers have let water firms get away with their destructive ways for far too long.

“There needs to be justice for victims of potential environmental crimes, especially swimmers and families simply wanting to enjoy beaches and lakes.

“Water company CEOs are pocketing millions in bonuses whilst swimmers get sick. This cannot carry on. If someone is poisoned by sewage, they should be compensated for it.”

He added: “The Liberal Democrats have exposed the sewage scandal and will continue to stand up for the victims of this environmental catastrophe, this amendment will hold the Conservatives and water companies to account.”

The Department for Environment, Food and Rural Affairs (Defra) and CCHQ have been contacted for comment.

It comes after Environment Agency figures showed a bigger percentage of bathing waters in England were rated poor this year than at any other time in the last eight years.

Of the 423 bathing waters measured in 2023, 18 were classed as poor, up from 12 last year and four in 2021.

The majority – 72.1% – were rated excellent but the figures show a marked increase in the number of swimming spots on the coast and in rivers that do not meet the minimum standard.

The figures prompted ire from opposition critics including Labour, who said the water industry is “broken after 13 years of Tory Government” and branded it “disgusting” that families and children cannot enjoy waters “without the threat of getting sick”.

Robbie Moore, the Conservative minister for water and rural growth, said the Lib Dems were engaging in a “short-term political stunt”.

He said: “We saw their lack of commitment to improving water quality in our rivers and coastal systems when they voted against the Government’s Environment Act at every opportunity.

“(Lib Dems) voted against the Storm Overflows Discharge Reduction Plan, which sets out stringent targets backed up by up to £56 billion capital investment, the largest infrastructure programme in water company history.

“This Conservative Government is forcing water companies to clean up their act, imposing over £141 million in fines that will be directly reinvested into tackling overflows and introducing unlimited fines on the industry.

“Only the Conservatives are taking the long-term decisions needed to ensure everyone in the UK benefits from the highest water quality as we work to protect our environment.”