Water company bosses have been told to "get a grip" or face jail terms for some of the worst pollution incidents happening on their watch.

Southern Water was branded "appalling" by the Environment Agency after it was given a one star rating for water pollution.

The agency’s annual environmental performance report for nine water companies said it was the “worst we have seen for years”, as serious pollution incidents increased to 62 in 2021, the highest total since 2013.

Southern Water, which is responsible for public wastewater collection in Kent, was one of two companies given just a one star rating – the lowest possible. Another four were rated only two stars, meaning they require significant improvement.

Over the last ten years the water company has only been rated three stars – out of a possible four – meaning it is a "good company" on three occasions. The last time was 2017 and it has been rated two or lower since.

The Environment Agency said water company bosses should face prison for the worst pollution incidents amid the sector’s "shocking" performance.

It comes as the watchdog concluded that despite continuing enforcement action against those breaching environmental laws, companies remain undeterred by the penalties currently imposed by the courts.

Emma Howard Boyd, Chair of the Environment Agency, said: "It’s appalling that water companies’ performance on pollution has hit a new low. Water quality won’t improve until water companies get a grip on their operational performance.

"For years people have seen executives and investors handsomely rewarded while the environment pays the price."

And as to where the blame lied she was clear who was responsible.

"Company directors let this happen," she added. "We plan to make it too painful for them to continue like this.

"The amount a company can be fined for environmental crimes is unlimited but fines currently handed down by the courts often amount to less than a Chief Executive’s salary.

"We need courts to impose much higher fines. Investors should no longer see England’s water monopolies as a one-way bet."

Toby Willison, Southern Water’s director of quality and environment acknowledged that the company’s performance in 2021 was not good enough and said they were committed to doing better for their customers.

“We know we have a long way to go, however, new investment and new ways of working, including major upgrades to our control centre and pumping stations, and the introduction of tens of thousands of digital monitors across our network, are already making a difference and delivering positive change.

“We continue to be open and honest about our environmental performance, and continue to work extremely closely with the Environment Agency and other stakeholders to improve and protect our environment.”

Southern Water was last year handed a record £90 million fine after pleading guilty to thousands of illegal discharges of sewage which polluted rivers and coastal waters in Kent, Hampshire and Sussex between 2010 and 2015.

So far five prosecutions have already concluded this year with more progressing in court.

Southern Water is also responsible for the public water supply and distribution in parts of Kent.

This week a major incident was declared on the Isle of Sheppey after an estimated 30,000 people were left without water for a second day amid a heatwave.

Taps ran dry on Tuesday and Southern Water apologised after admitting it was taking longer than expected to restore supplies.

It's expected the failing water company will fork out around £2m in compensation to Islanders affected by the shortage.