The UK’s biggest ever dinosaur trackway site has been discovered in a quarry in Oxfordshire.

About 200 huge footprints, which were made 166 million years ago, criss-cross the limestone floor.

They reveal the comings and goings of two different types of dinosaurs that are thought to be a long-necked sauropod called Cetiosaurus and the smaller meat-eating Megalosaurus.

The longest trackways are 150m in length, but they could extend much further as only part of the quarry has been excavated.

“This is one of the most impressive track sites I’ve ever seen, in terms of scale, in terms of the size of the tracks,” said Prof Kirsty Edgar, a micropalaeontologist from the University of Birmingham.

“You can step back in time and get an idea of what it would have been like, these massive creatures just roaming around, going about their own business.”

The tracks were first spotted by Gary Johnson, a worker at Dewars Farm Quarry, while he was driving a digger.

“I was basically clearing the clay, and I hit a hump, and I thought it’s just an abnormality in the ground,” he said, pointing to a ridge where some mud has been pushed up as a dinosaur’s foot pressed down into the earth.

“But then it got to another, 3m along, and it was a hump again. And then it went another 3m – hump again.”

Another trackway site had been found nearby in the 1990s, so he realised the regular bumps and dips could be dinosaur footprints.

“I thought I’m the first person to see them. And it was so surreal – a bit of a tingling moment, really,” he told BBC News.

This summer, more than 100 scientists, students and volunteers joined an excavation at the quarry which features on the new series of Digging for Britain.

The team found five different trackways.

Four of them were made by sauropods, plant-eating dinosaurs that walked on four legs. Their footprints look a bit like an elephant’s – only much much bigger – these beasts reached up to 18m in length.

Another track is thought to have been created by a Megalosaurus.

“It’s almost like a caricature of a dinosaur footprint”, explained Dr Emma Nicholls, a vertebrate palaeontologist from the Oxford University Museum of Natural History.

“It’s what we call a tridactyl print. It’s got these three toes that are very, very clear in the print.”

The carnivorous creatures, which walked on two legs, were agile hunters, she said.

“The whole animal would have been 6-9m in length. They were the largest predatory dinosaurs that we know of in the Jurassic period in Britain.”

The environment they lived in was covered by a warm, shallow lagoon and the dinosaurs left their prints as they ambled across the mud.

“Something must have happened to preserve these in the fossil record,” said Prof Richard Butler, a palaeobiologist from the University of Birmingham.

“We don’t know exactly what, but it might be that there was a storm event that came in, deposited a load of sediments on top of the footprints, and meant that they were preserved rather than just being washed away.”

The team studied the trackways in detail during the dig. As well as making casts of the tracks, they took more than 20,000 photographs to create 3D models of both the complete site and individual footprints.

“The really lovely thing about a dinosaur footprint, particularly if you have a trackway, is that it is a snapshot in the life of the animal,” Prof Butler explained.

“You can learn things about how that animal moved. You can learn exactly what the environment that it was living in was like. So tracks give us a whole different set of information that you can’t get from the bone fossil record.”

One area of the site even reveals where the paths of a sauropod and megalosaurus once crossed.

The prints are so beautifully preserved that the team have been able to work out which animal passed through first – they believe it was the sauropod, because the front edge of its large, round footprint is slightly squashed down by the three-toed megalosaurus walking on top of it.

“Knowing that this one individual dinosaur walked across this surface and left exactly that print is so exhilarating,” said Dr Duncan Murdock from Oxford University.

“You can sort of imagine it making its way through, pulling its legs out of the mud as it was going.”

The future fate of the trackways hasn’t yet been decided but the scientists are working with Smiths Bletchington, who operate the quarry, and Natural England on options for preserving the site for the future.

They believe there could be more footprints, these echoes of our prehistoric past, just waiting to be discovered.

The excavation is featured on Digging for Britain on BBC Two at 20:00 on Wednesday 8 January. The full series will be available on BBC iPlayer on 7 January.