Fears over 'very lost' beluga whale in River Thames

Media captionWATCH LIVE: Aerial shots after reported sighting of a Beluga whale in the River Thames.

A beluga whale was spotted in the River Thames outside the British capital on Tuesday, officials said.

Beluga whales are usually found in the Arctic Ocean, with males measuring as long as 5.5 metres and can also weigh up to 1,600kg.

There have only been around 20 sightings of beluga whales off the United Kingdom coast previously (file photo).

"If this animal is a beluga whale, it is very far from home", London's Natural History Museum wrote on Twitter.

"Beluga whales inhabit cold, arctic waters off Greenland, Svalbard and in the Barents Sea", the group said in a statement.

It said it is ready to provide help to the whale if asked to do so by other agencies.

The WDC's Danny Groves told the UK Press Association, "He or she is obviously very lost and quite possibly in trouble".

Babey said it was unclear why this one had lost its way and come into the Thames, though it would be unlikely to have lost its way due to storms or because it was following prey.

Beluga whales were last spotted in the United Kingdom three years ago off the coast of Northumberland and Northern Ireland, but sightings were "extremely rare", spokeswoman Julia Cable said.

A bottle-nosed whale became stranded in the Thames for two days in 2006, but died from convulsions as it was being rescued.

"The Thames beluga is back feeding in its favoured spot around the barges on the Kent side", he said urging all boats to "keep clear and let it alone".

Belugas are able to produce sounds such as chirps, clicks, whistles and squeals, giving them the nickname "the canary of the sea".