LONDON - A BRITAIN-based palaeontologist believes he has found the world's first known Tyrannosaurus rex footprint, he told a BBC television documentary on Wednesday.

Phil Manning said he has high hopes the one square metre print, from the famed Hell Creek area of the northwest US state of Montana, is from the flesh-eating giant, although 100 per cent certainty is impossible.

'People have been trying to find T.rex tracks for a hundred years,' Manning, who specialises in Jurassic and Cretaceous period dinosaur tracks, told the BBC.

'Unless you come across an animal dead in its tracks you can't say for definite what left them.

'However with information available about the numbers of T.rex in the rocks of the Hell Creek formation, it is the closest we have got so far to discovering a tyrannosaur track.'

Mr Manning, whose work still needs to be peer-reviewed, suggested the 67-million-year-old print 'could only' be one of the two species previously found in Hell Creek, Nanotyrannus or its bigger relative Tyrannosaurus rex.

'The size of the footprint at 76 centimetres in length suggests it is more likely to be the latter,' said the academic, from the University of Manchester, northwest England.

'There is no such thing as a truth in science, so for us this is as close as we get to what I think is a fantastic find.'

Tyrannosaurus rex, which stood about six metres tall, 12 metres long and weighed about seven tonnes, was one of the last dinosaurs to roam the earth before the entire species was wiped out about 65 million years ago.

All T.rex remains have been found in the Hell Creek area. Manning located the giant footprint last year.

Angela Milner, associate keeper of palaeontology at London's Natural History Museum, said she was interested in comparing Mr Manning's discovery with one found in New Mexico in 1993 that was given the name 'Tyrannosaurus pillmorei'.

'That print was about four centimetres longer... and is also thought to have been made by a T.rex,' she said.

'It is never possible to be certain of the animal that made fossil footprints as they do not die conveniently at the end of their tracks.

'However both these prints occur in rocks of the right age, they definitely were made by large carnivorous dinosaurs - and the only one that was that large enough to leave such a huge footprint was Tyrannosaurus rex.' -- AFP