Increasing numbers of seals, porpoises and dolphins are being spotted along the Thames, with many making it as far as west London, an online map reveals.
The Zoological Society of London has recorded 1,262 sightings of marine mammals in the river by members of the public since 2004, with many of those animals seen in the last few months or years.
They have all been charted on an online map, which shows sightings as far west as Hampton, in the borough of Richmond.
The society has urged more people to report sightings as it says the presence of such "charismatic top predators" is an excellent indicator of the waterway's biodiversity.
In 1957, the Thames was so polluted it was declared biologically dead, but it is now much cleaner and is home to a wide range of wildlife.
The majority of sightings have been around Canary Wharf or further east towards the river's mouth, but there have been several in west London.
Those include a harbour seal spotted around Hammersmith Bridge, in February, by Nathalie Mahieu, who captured the footage above of its journey upstream.
In May this year, James Lee spotted a harbour porpoise in the river between Chiswick and Barnes bridges.
In March, Jamie Adams saw a grey seal chomping on a fish as it headed downstream near Chelsea Harbour.
The latest sightings have all been recorded on the ZSL's map here, where you can add reports of marine mammals you have seen.
The ZSL says on its website: "The Thames Estuary is home to harbour seals, grey seals, harbour porpoises and sometimes even dolphins and whales!
"ZSL has been collecting public sightings of these marine mammals since 2004 and they are frequently sighted all the way up to Richmond.
"These sightings form a crucial part of our understanding of the biodiversity in the Thames and help us conserve these charismatic top predators.
"If you are lucky enough to see a marine mammal, please follow our code of conduct and report your sighting below."
