Fears are mounting for as whale, believed to be a rare humpback, which has appeared in the River Thames in England.

There were six sightings of the massive marine mammal – said to be up to a staggering 32-feet – in the river yesterday.

And today it was spotted again in the water near the Dartford Crossing between Kent and Essex.

If it is a humpback as believed, it would be the first time in 10 years one of them has been spotted in the Thames.

The rare species can weigh up to 7,000 pounds in adult form.

The whale has already been named online as “Hessy” – and was seen between Crayford Ness and the Queen Elizabeth II Bridge in Dartford, Kent – more than 60 miles in land from the sea – after midnight.

It comes just over a year since Benny the Beluga set up home further downstream at Gravesend last summer.

Twitter users have poured out sympathy for the animal with one imploring “hope it finds its way out again”.

Martin Garside, from the Port of London Authority, said the size of Hessy has ranged from between 16-feet and 32-feet.

“There were a number of sightings by boats on the river during the course of yesterday,” said Garside.

“We have not had any confirmed sightings today. As far as the reports yesterday go, it is a dark-colored whale with a small dorsal fin – so it is not anything like the beluga. This animal is darker.All we know at this stage is it is dark-colored.

‘NOT AN EVERYDAY SIGHT’

“There are varying estimates of size, between five meters and 10 meters. That is consistent in description with a humpback and also other types, including a minke whale. We are working with British Divers Marine Life Rescue, who are monitoring the behavior of the whale and the type of species. It is not an everyday sight, although we have had a number of whales in the Thames.”

Garside added that it was “too soon to assess” how long the whale could be in the river for.

The British Divers Marine Life Rescue service confirmed the sighting of the whale.

A member of the team said: “We observed the humpback whale in the Thames Estuary for just over three hours today, the whale was diving and surfacing at approximately 5-6 minute intervals, slowly moving down river with the outgoing tide.”

The whale has been nicknamed Hessy by some Twitter users.

One account, called Girl About the Thames, wrote today: “Hessy The Thames Humpback Whale was sighted at Ford Dagenham this morning. Unfortunately it’s headed further in.”

Police Constable Dempster, a member of the Metropolitan Police Marine Policing Unit, spotted the sea creature during an overnight patrol.

“It was spectacular! Was gobsmacked it was so big. Would estimate about 15 meters,” he tweeted.

In September 2018 a beluga whale – normally found in the Arctic – was spotted in the River Thames near Gravesend, Kent.

It stayed in the river for around nine months before it eventually made its way out back out towards the North Sea.

Named Benny by animal lovers, it attracted large numbers of visitors who came down to the shore to catch a glimpse of it.

Humpback whale in the River Thames.
Humpback whale in the River Thames.SWNS