The chicken liver sponge has sailed through a test of its ability to filter pollutants in a harbour in Spain’s Costa Brava

In the polluted waters of Marina Palamós on Spain’s Costa Brava, Manuel Maldonado, a sponge biologist, noticed something unusual last month: red starfish had started settling in the area.

Nearly two years earlier, the Spanish National Research Council scientist and his colleagues had begun transplanting sea sponges into the port to study whether they could survive in its polluted waters.

Checking for sewage spills has become as normal as checking the weather forecast, say swimmers on East Sussex beaches

• South West Water has worst environmental record in England, analysis shows

“I’m furious,” says Jo Armstrong, 75, sitting on Brighton beach with her daughter and granddaughter.

Armstrong lives in Lewes, a town 8 miles from Brighton, and usually goes swimming in nearby Seaford in East Sussex every day. But over the past week the water there has been too polluted to swim. “Brighton beach was the only place that stayed clean,” she says.

Checking for sewage spills has become as normal as checking the weather forecast, say swimmers on East Sussex beaches

• South West Water has worst environmental record in England, analysis shows

“I’m furious,” says Jo Armstrong, 75, sitting on Brighton beach with her daughter and granddaughter.

Armstrong lives in Lewes, a town 8 miles from Brighton, and usually goes swimming in nearby Seaford in East Sussex every day. But over the past week the water there has been too polluted to swim. “Brighton beach was the only place that stayed clean,” she says.