Porpoise spotted in River Thames at Twickenham in west London

Porpoise spotted in River Thames at Twickenham in west London

A porpoise has been spotted in the River Thames in west London.

The marine mammal was in the water by Eel Pie Island in Twickenham, about 50km inland from the mouth of the Thames, on February 29.

The delighted passerby who spotted it described it as “a rare sighting on a rare day”.

It is not the first time cetaceans have been spotted so far inland.

Conservation charity ZSL previously said dolphins and porpoises have in the past been sighted at Teddington Lock in south-west London, around two miles further inland than where the porpoise was spotted on Thursday.

The sighting comes after a pod of dolphins were spotted in the Thames in east London.

The dolphins were filmed swimming as far inland as Canary Wharf last week, as well as in the river by Deptford, Greenwich and Woolwich.

On Sunday dolphins - believed to be the same pod - were filmed swimming in the Thames at Northfleet in Kent, by a delighted RNLI lifeboat crew returning from a call-out.

“It was an incredible sight,” said Gravesend lifeboat volunteer John Robinson. “We spotted the dolphin-like fins at first.

“There were two adults and a calf. They were approximately two metres in length - incredible to witness right here on the River Thames, especially when they were jumping out of the water.”

The RSPCA urged people to “behave considerately” around the animals.

“We are aware of these dolphins and really appreciate that people want to make sure they're safe,” said a spokesperson. “We are ready to provide appropriate assistance if requested.

“It is not unusual for dolphins to find their way into harbours or rivers such as the Thames and they have been known to travel inland quite some distance. They are usually just looking for more food and generally they find their way out to sea again.

“We ask the public to do their bit and behave considerately to the dolphins. It’s important that disturbance is kept to a minimum, to maximise the chances of them returning to the open sea under their own steam.”

A spokesperson for British Divers Marine Life Rescue (BDMLR) said it understands the dolphins have been leaving the Thames as the tide goes out.“We have been aware of the dolphin sightings in the Thames and while it's not an everyday occurrence, dolphins and porpoises do venture up the estuary usually following food and can make it as far as Canary Wharf which is where they were seen this week,” said a spokesperson last week.

“On both occasions this week the dolphins have left the river on the falling tide which is to be expected.

“There have been some recent sightings of a pod of dolphins in the River Medway, so it's likely that these are the same animals.

“The main risk for dolphins in the Thames is river traffic, the large vessels shouldn't pose too much of a risk for them, but smaller boats can be a problem.”