A 44ft (13m) long whale has died three hours after becoming stranded on a beach on Teesside.
Police alerted the RNLI after spotting the 20 tonne stricken mammal on Redcar Beach, just after 0620 BST.
A rescue bid started which involved trying to keep the adult sperm whale wet until high tide but it died.
Richard Ilderton, of British Divers Marine Life Rescue, said the North Sea was not a suitable environment for such a large creature.
RSPCA officers were involved in the rescue attempt, along with those from the Coastguard and Cleveland Fire Brigade, while RSPCA vets assessed the mammal's condition.
An RNLI spokesman said: "We don't know the reasons but usually when they get to this situation the conclusion is that they don't survive.
"A post mortem will be carried out on the whale and then it will be up to the local council to dispose of it."
Crowds went to the beach to see the whale.
Redcar and Cleveland Council said cordons had been put up around the whale, which is due to remain on the beach overnight, watched by security guards.
Mr Ilderton said: "While we have whales in the North Sea, it is not a suitable environment for a sperm whale because the food supply is not there.
"It doesn't eat, it becomes malnourished, it becomes dehydrated because whales do not drink - they get their liquid from their food.
"It can cause all sorts of health problems and ultimately results in something like this happening."
He said the whale's death might actually have been the best outcome.
"If we were able to put the animal back out to sea, all we would be doing is putting it back out to starve, which is massively cruel and against what we want to do," he said.
Robbie Marsland, UK Director of International Fund for Animal Welfare, said whales stranded for a variety of reasons.
He said: "While it is not possible to pinpoint the cause in every case, we do know that human activity in the seas is increasing the threats to these highly intelligent and complex marine mammals.
"Manmade ocean noise, from shipping, oil and gas excavation and naval sonar, makes it ever harder for whales to navigate, communicate, find food or mates and avoid prey."