Environment chiefs are struggling to contain a crude oil spillage that has been spreading down the River Lea through Hackney since Sunday.

The thick, black oil is thought to have entered the water at Tottenham and has now drifted as far south as Homerton and as far north as Stonebridge Lock.

Boaters believe not enough has been done to stop the oil spreading and say they are worried for their health – and their vessels.

Boat owner Sophie Scott told the Gazette: “It’s acrid.

“It’s thick – across the whole river.

“You can see it on all the birds, and goodness knows what’s happening to the wildlife under it – or to our boats.

“We’re breathing it in. It’s in our environment – we’re breathing it in on a daily basis.”

She added: “There was some clean-up at Tottenham but as of yesterday it’s made its way down to Homerton.

“The booms [long barriers to stop the spread of oil] were in place for about 24 hours.

“Whatever tidy-up was done, it’s just carried on down the river.

“All the boaters are willing and happy to help, but we need the tools to do so. If the Environment Agency distributed pads to all of us we could put them around our boats to soak up the oil.”

Like many who use the river, Sophie is worried about her pet cat falling in to the slick and has kept her indoors.

A neighbour, who has lived by the canal in Lower Clapton for seven years, told the Gazette the spill was “far and away the worst pollution we’ve seen”.

Andrew Northwood said: “It’s thick and black – it almost looks like waste oil.

“We normally have quite a lot of water birds here – ducks, swans, geese – and apart from a couple of coots they’ve all gone.”

The Canal and River Trust has handed over responsibility for the spill to the Environment Agency.

“We were alerted to the oil spill on the River Lea on Sunday,” said a spokesman, “and had teams out straight away to put in booms [long barriers] to contain the spread and absorbent pads to collect the oil.

“The Environment Agency have continued work out on the water throughout the week and we’re providing any support they might require.

“It goes without saying that any pollution like this is concerning. We acted promptly to stop it spreading, but there is a lot of work to be done to clear the oil from the water.”

The Environment Agency said in a statement: “We received notification of an incident of oil pollution on the River Lee [the Lea’s name further north], near the Middlesex Filter Beds on February 11.

“Our officers have been working alongside a specialist contractor to clear up the spillage and we are investigating the source of the pollution.

“Clear up work will continue today and if necessary tomorrow.

“Our officers will also be monitoring the river over the weekend.

“If people suspect pollution in a river they should report it to our incident hotline on 0800 807060.”

Meanwhile, 15 swans have been taken in to The Swan Sanctuary in Shepperton to have oil removed from their wings – and could face a stay of up to a month while their skin recovers.

“It’s very bad,” said volunteer Gill Walker. “Whatever this is – it’s certainly got a lot of diesel in it – it gets onto their skin and it’s corrosive. And where they’re constantly preening, it’s getting into their digestive systems and they are constantly exposed to it.

“It isn’t just what you see. The oil strips them of their natural waterproofing, which makes them waterlogged, and spoils their insulation [so even in warmer temperatures] they can suffer from hypothermia.”

She added the sanctuary had just released 40 swans who were rescued following an oil spillage in the same part of the river over Christmas.

The sanctuary relies on volunteers and donations. You can visit theswansanctuary.org.uk to find out more.