This swan is covered in engine oil polluting a park lake in Ilford after allegedly being dumped by “irresponsible” fly-tippers.

The Environment Agency believes that people have been illegally pouring oil either directly into the lake, in South Park, or into drains that feed it.

Tony Webb, of the South Park Users Group, said workers at a swan sanctuary told him oil in feathers is not as dangerous for water birds as ingesting the oil.

He added: “Despite the best efforts of the Environment Agency and Thames Water, we still have irresponsible people pouring their used engine oil down drains.

“This is not the only form of pollution we suffer from on the lake, and in the park in general.”

The oil entered the lake earlier this month in the north part of the waterway, in South Park Road.

An Environment Agency spokesman said the amount found “suggested fly-tipping from a single engine”.

He added: “The Environment Agency have been working Thames Water, who are leading on the effort to clear up the remaining oil and trace where it may have come from.

“We will continue to monitor the situation and assist Thames Water where required.”

It is not the first time water birds in the park have been endangered by pollution.

In 2011, cygnets had to be saved by a sanctuary after they were left covered in cooking oil poured into the lake.

Anne Hoad, of the South Park Users Group, said the two incidents are the tip of the iceberg when it comes to pollution in the park.

She added: “A lot of people feel the need to feed the wildlife and they put down mouldy food, leftover dinners and even meat.

“It really is a problem – it’s not good for the wildlife and it’s bad for the park.”

One cygnet is being monitored by a sanctuary after it hatched deformed.

It had no rudder tail, making it difficult to swim.

Anne said the defect could have been caused by the parents having a poor diet.

She added: “We get bottles, bags, cans and all sorts in the lake. It’s got to stop.”