COCAINE snorted by Londoners is polluting the Thames — and making eels hyperactive.

There are even fears the critically endangered fish could become too confused to migrate the 3,000 miles across the Atlantic to breed.

Cocaine enters the river in users’ urine via treated sewage. Untreated sewage can also get in following storms.

Researchers at King’s College monitored levels near the Houses of Parliament and found consistently high amounts.

In many other cities, cocaine use peaks at weekends.

The experts said: “London is known as one of the highest consumers of cocaine and this suggested every day usage.”

They want water treatment systems improved but noted the giant Tideway Tunnel sewer should stop any waste entering the river when it opens in 2023.

The London team detected cocaine levels in the river at more than one microgram per litre of untreated wastewater.

Scientists in Italy have found 0.02mg of cocaine per litre is enough to send eels in tanks into a frenzy, and causes damage to their muscles.