Stranded on marshland just off the Norfolk coast and hundreds of miles away from its natural habitat, there was little nature wardens could have done to save this young whale.

The female Sowerby's beaked whale, which weighed around 450kgs, beached in Thornham, near Hunstanton, on Monday morning and struggled to move back into the water as the tide rapidly went out.

The helpless creature was seen 'thrashing about' from a distance by Paul Seymour, assistant warden at the Norfolk Wildlife Trust, who then called for others to help.

But the bleeding whale, which measured nearly four metres in length, was eventually euthanased after a torrid few hours out of the water.

It is only the third recorded sighting of a Sowerby's beaked whale in Norfolk with the other sightings being in 1952 and in Blakeney Point in 2009.

Gary Hibberd was one of the first Norfolk Wildlife Trust wardens to arrive at the scene to try and help the whale.

He said: 'We were out carrying out our normal day-to-day duties when Paul [Seymour] called us at about 9am to say he could see something thrashing about on the salt marshes.

'When we arrived she was still alive and was trapped on high ground about a metre away from a deep creek.

'But there was no way we were going to push her or drag her to the creek without causing her a lot of damage.

'It was obvious from the start she wasn't going to survive and there was already a lot of blood around her as well so there were four of us beside her just trying to do the best we could.'

Nicola Walker, from the RSPCA, said the charity was notified about the stranded whale and staff, along with a vet, attended the scene a couple of hours later.

'When they arrived it was clear that the large whale was in a collapsed state and was distressed and dying,' she said.

'The location where the whale was found made it impossible to return it to deeper waters and it was decided that the best thing for the whale was to end its suffering and it was put to sleep.

'Everyone involved was very upset by the sad conclusion to this incident. The relevant bodies have been informed and pathologists from London Zoo are expected to remove its body.'

Dr Paul Jepson was one of the pathologists called to the North Norfolk salt marsh.

He said: 'These whales normally live in very deep water out in the Atlantic and feed on squid and get completely lost in the North Sea.

'They get all their food and water from eating squid so with no squid in the North Sea, this whale would have become dehydrated quickly.

'We won't know why she ended up in the North Sea and then stranded at Thornham but she wasn't very old so she may have been separated from her mum and then couldn't find her way home.

'It would've been completely hopeless to try to re-float this whale in this situation because she was far away from home and in a poor condition. She wouldn't have survived for much longer.'

He added: 'In the water these whales are weightless but once they are on land they cannot support their own body weight. They have a lot of heavy muscle and tend to crush themselves and eventually their lungs collapse.'

As of August 2010, only 46 stranded Sowerby's Beaked Whales have been recorded around the UK coastline by the Cetacean Strandings Investigation Programme (CSIP) since its inception in 1990.

One of these strandings happened at Blakeney Point in August 2009 and saw a much larger whale stuck and in need of human help.

The helpless whale was then manhandled by National Trust wardens Richard Berridge and Eddie Stubbings on to a stretcher and dragged to the sea with the help of six holidaymakers.