A new study has revealed that Wiltshire’s world-famous Stonehenge Neolithic monument may have originally been situated in Wales and then moved to Salisbury Plain more than 5,000 years ago.

In a new documentary on BBC 2 Television tonight,  BBC Two's Stonehenge: The Lost Circle Revealed, Stonehenge expert Professor Mike Parker Pearson reveals his new theory on where Stonehenge originally came from and why it was moved to Wiltshire.

He says that hidden below the ground on a stunning Welsh mountainside is the answer to one of the last remaining secrets of Stonehenge.

Under a former peat bog is the proof that the iconic World Heritage site is in fact a second-hand monument which was moved 180 miles to Wiltshire.

This surprising discovery is the result of a decade-long quest by Professor Parker Pearson, of University College in London, working alongside a dedicated multi-disciplinary team of academic experts from across Britain and Europe.

Together, they pooled their different specialisms and pioneered new techniques to uncover the origins of the world’s most famous Neolithic monument.

Along with the revelation comes a new understanding of the different peoples who lived in Britain 5,000 years ago and how they interacted with each other to build Stonehenge.

Professor Parker Pearson said: “We've discovered that Stonehenge's origins were 180 miles away in the Preseli Hills of west Wales where its smaller megaliths - known as bluestones - were quarried.

“These Welsh stones were the first to be put up at Stonehenge but before they arrived on Salisbury Plain, it seems some of them once formed an earlier stone circle that was dismantled, moved and rebuilt as the iconic Stonehenge monument we know today.

“That first Welsh circle, Waun Mawn, was at the centre of a complex of Neolithic ceremonial monuments so Preseli was already a special place for Neolithic people. When the bluestones were erected at Stonehenge around 3000 BC, people were buried alongside them.

“Some of these had lived far to the west, most likely in west Wales. We think they may have taken part in a migration, bringing the circle's stones as their ancestral symbols of identity to make a new start in this other special place.

"This extraordinary event may also have served to unite the peoples of east and west Britain.”

Asked why he thinks Stonehenge captures so much interest from the public, Prof Parker Pearson replied: “That for me is one of the greatest mysteries of Stonehenge! Like certain celebrities, it's famous for being famous.

“I think public interest really took off in the 1960s and 1970s after von Daniken's bogus theories about ancient aliens and the Stoned-henge free festivals.

"Having hit that high, it's become a touchstone for journalists as the one European prehistoric site they know people have heard of, so it gets star-billing every time it's in the news.”

The BBC film crew suffered many challenges to bring the programme to the screen, particularly the wet and windy weather in Wales.

Prof Parker Pearson said: “Wales can have spectacularly fine weather but it can also be extremely wet and windy even in summer, especially if you’re halfway up a mountain.

“That last season of digging at Waun Mawn was the worst weather in the whole seven years of our project, with torrential rain and storm-force winds.

“Normally we try not to dig in heavy rain and high winds but in the last few days we had to fill in our trenches by hand (no machinery is allowed on the heathland) and we couldn't go home until it was done.

"I used to dig in the Outer Hebrides, one of the wettest and windiest places on the planet, so at least I'm used to it!”

He added: “People of the Neolithic were extraordinary. Although they lived 200 generations ago, they were no less clever or determined than us. Of course, they had very different motivations which is why they are so fascinating.

“Moving hundreds of tons of big stones nearly 200 miles from the Preseli Hills to Salisbury Plain seems ridiculous because it's hard for the modern mind to understand how mere stones could have been so valuable.

"But it seems these megaliths weren't just luggage but powerful symbols of these people's very being.”

In the documentary, which is being broadcast at 9pm tonight on BBC2 TV and which is presented by Professor Alice Roberts, viewers will see the programme makers travel to various locations to film.

Prof Parker Pearson said: “I've been leading a team researching Stonehenge since 2003, digging within and around the monument until 2009 when we discovered a site two miles away (Bluestonehenge) where the Welsh stones had also been put up.

“It was then that we realized that the bluestones' source held the key to understanding the origins of Stonehenge so we moved the project to Preseli and began digging there in 2011.

“The big breakthrough had just been made by geologists Rob Ixer and Richard Bevins, pinpointing one of the quarries. Although Richard's lab is in Cardiff at National Museums Wales, he's been working with Jane Evans at the British Geological Survey in Nottinghamshire.

“Most of the research takes place long after excavations have finished and I have to travel to many different places to coordinate the many experts involved.”

The filming locations included:

• Stonehenge, Wiltshire - English Heritage

• Waun Mawn - Neolithic stone circle

• Pembrokeshire - Barony of Cemaes

• Craig Rhos-y-Felin – Quarry

• Pembrokeshire - Mrs D Davies

• Carn Goedog, Pembrokeshire - Quarry

• British Geological Survey - Nottinghamshire

• Ancient Technology Centre, Dorset - Dorset Council