Update: RNLI has updated their statement to clarify that the animals the crew saw are believed to be dolphins, not porpoises as originally identified.

A lifeboat crew had a rare encounter with three dolphins near Dartford in the River Thames today.

Gravesend's RNLI volunteers spotted the creatures in the River Thames at around midday on February 25.

The crew onboard the lifeboat “Olive Laura Deare II” were finishing an assignment given by HM Coastguard, when they saw the dolphins in the water at Northfleet.

After the encounter, the crew was back in Gravesend Reach, refuelled, and ready for service by 12.14pm.

RNLI crew member John Robinson said: “It was an incredible sight, 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”

Gravesend RNLI Station Manager Ian Smith added: “We often see Seals whilst out on the Lifeboat, but Porpoises and Dolphins are definitely on the rarer side of marine mammals we spot!”

The Thames is a habitat for a myriad of wildlife, including migratory and overwintering birds, 125 species of fish, and various marine and terrestrial mammals.