The one-off episode will follow the excavation of the skull of a Pliosaur, one of the most fearsome predators of prehistoric Britain. Pliosaurs were enormous creatures who inhabited the seas when dinosaurs ruled the earth 150 million years ago.

Sir David Attenborough will join the dig to uncover the skull, going on to find out more about the creature with help from expert scientists and palaeontologists. Attenborough will explain how the Pliosaur looked and behaved as well as how it hunted its prey, using state-of-the-art CGI to visualise the colossal size and strength of the creature.

Attenborough, speaking to the BBC, said: “Pliosaurs were the biggest and most formidable hunters in the Jurassic seas, the marine equivalent, you might say of T. Rex. The skull of this one is, by itself, over two metres long and armed with massive fangs.”

Pliosaurs refer to a large prehistoric reptile group. Fossil experts deem this particular finding to signal a completely new species of Pliosaur, which Attenborough and the team investigate.

Mike Gunton, Executive Producer, said: “It’s wonderful to be back on location with David - his eyes absolutely lit up when we told him about this amazing find – he couldn’t wait to join the ‘dig’ and get a first look at the fossil bones for himself.”

Jack Bootle, Head of Commissioning, Specialist Factual, added: “This film promises to be a thrilling trip through time to a moment when monsters ruled the seas around Britain. I can’t wait for viewers to experience it.”

Attenborough and the Giant Monster (working title) will be filmed in the UK, documenting the same seas Pliosaurs used to hunt in.

The film will air on BBC One and will be available to stream on BBC iPlayer.