The first pieces of the 26ft-long creature were unearthed from clay cliffs on the Isle of Wight's south coast as long ago as 1978. But only now have enough of the fossil bones been found to form a complete skeleton. The dinosaur has been named Neovenator Salerii after the Salero family on whose land the remains were found.
Experts confirmed yesterday that Neovenator is a previously unknown species, distantly related to the Allosaurus from North America but lighter and quicker.
It is the first European member of a "super-family" of upright standing carnivores known as the Allosauroidae. The other members are Allosaurus and the recently discovered Cacharodontosaurus from North Africa.
Excavation of the Isle of Wight site was halted after about 10 years but re-started seven years ago when erosion of the cliffs exposed more bones. Steve Hutt, curator of the island's geological museum, who led the team, said: "It was pure coincidence that a local collector found the original site about seven years ago. Since then we have been excavating the site and decided last year that we had got enough of this animal together to publish a scientific description.
"It's a very exciting find because this is the first member of Allosauroidae to be found in Europe."
He said Neovenator, which would have weighed about three-quarters of a ton, had a metre-long skull armed with razor-sharp teeth and limbs with claws up to 13cm long.
It probably preyed on herds of Iguanadon, a plant-eating dinosaur which was common in the Cretaceous period.