Why are bizarre metal pillars popping up in the British countryside? From the work of UFOs to mystery collectives planting the monoliths by helicopter in the dead of night and Banksy rumours... all the theories explained

Humans have long been obsessed with the idea that we are not alone in the universe - which is why the appearance of random metal pillars in the British countryside have sparked fresh theories over whether a third kind truly does exist.

Last weekend, yet another mysterious shiny silver structure was spotted by walkers on Hay Bluff, near the town of Hay-on-Wye. 

It was the latest in a series of bizarre structures to crop up, with pillars also spotted on a beach in the Isle of Wight, at the top of Glastonbury Tor, in the middle of Merry Maidens stone circle in Cornwall and on the fields at Dartmoor National Park.

The appearances that range from 2020 to last weekend have led to much speculation over who has put them there and why, with some even pondering whether or not the objects could be of extra-terrestrial origin. 

Local builder Craig Muir, who discovered the 10ft monolith sticking up out of the mud, said he assumed it was 'some sort of a UFO' while out walking.

The latest sighting remains shrouded in mystery as no-one has come forward to claim responsibility for the Welsh metal pillar which bears striking similarities to the one featured in the Stanley Kubrick film 2001: A Space Odyssey. 

The pillars have turned up in the UK following a spate of monoliths appearing around the world in 2020, including in Romania and the Utah desert. 

Last weekend, yet another mysterious shiny silver structure was spotted by walkers on Hay Bluff, near the town of Hay-on-Wye 

While some speculated that the structure could be the work of aliens or a sign of life on Mars, others said it was an elaborate piece of artwork

The latest sighting remains shrouded in mystery as no-one has come forward to claim responsibility for the Welsh metal pillar which bears striking similarities to the one featured in the Stanley Kubrick film 2001: A Space Odyssey (pictured)

Conspiracy theorists believe that aliens are behind the structures but others have speculated that helicopters could be dropping them off in the dead of night.

Since there is no way to drive up to the top of the hill, Mr Muir suggested it could have been taken by a group of people or dropped off by the chopper on its spot.

'It didn't seem like it was chucked in there, instead it has been accurately put in the ground,' he said.

'However, there were no obvious tracks around it and one would think that there would be a lot of mess around it, but there wasn't.'

The latest discovery is similar to the structure found on Compton Bay on the Isle of Wight four years ago.

A number of photos from various different angles suggested that  the monolith was buried in the sand and offers out a perfect reflection. 

How the object ended up on the beach was unclear, as it is only accessible via a footpath.

Locals were quick to question whether images of the monolith posted on social media had been 'photoshopped' or if it was 'just a late April Fool's joke'.

On December 12 2020, local resident Luke Brown stumbled across another imposing monolith in Cornwall and captured a video of the metallic object

 But photographer Alice Williams insisted it was real, sharing snaps of the eight-foot-tall structure at sunset in a local Facebook group.

Elsewhere, on December 12 2020, resident Luke Brown stumbled across another imposing monolith in Cornwall and captured a video of the metallic object.

He said: 'I was left in shock and awe earlier at finding a monolith at the centre of the Merry Maidens stone circle near sunset, the one time I left my camera at home.

'It was a thing of beauty but I can't help thinking of the damage that may have been done at this beautiful protected natural heritage site.'

The Merry Maidens also known as Dawn's Men - a likely corruption of the Cornish Dans Maen Stone Dance - is a late neolithic stone circle.

Just one day prior to the monolith being captured in Cornwall, another pillar was also spotted in Dartmoor National Park, Devon. 

The structure was spotted on Dartmoor by photographer Sarah Clarke, who captured a shot of the monolith, before posting to X, formerly Twitter.

Dartmoor National Park swiftly removed the monolith after a picture of it was posted by photographer Sarah Clarke, with the body saying that the moorland is protected

Only 48 hours prior to the sighting of a monolith in Dartmoor National Park, another similar structure was seen on top of a hill in Glastonbury with 'Not Banksy' etched on it

She reassured her followers that the image was not made using photoshop software, stating: 'So, a very exciting morning - it's a real thing. 'Anyone who knows me, knows I just can't do Photoshop so, take it from me.'

Mark Bullock, who went to look at the pillar himself, said its vantage point on the hill made it appear like 'something was wrong with the sky'. He added: 'It was a bit surreal.'

Dartmoor National Park swiftly removed the monolith after Ms Clarke's post, saying that the moorland is protected.

Just 48 hours prior to the Dartmoor sighting, another similar monolith was seen on top of a hill in Glastonbury with 'Not Banksy' etched on it.

Walkers discovered the large silver structure at Glastonbury Tor - an ancient hill linked to King Arthur and Celtic mythology.

It is believed the monolith was placed there overnight before it was felled by a gust of wind.

On December 6 2020, another monolith was found by beachgoers at Compton Bay on the Isle of Wight

The shiny triangular pillar features a stencil drawing of a rat, similar to the style used by street artist Banksy.

Michelle Cowbourne spotted the metal structure at the National Trust site while on her regular morning walk. 

'I walked up the long slope side and this was on the other side and when I saw it I couldn't believe my eyes,' she said. 'I just thought what on earth is that.

'There were two big metal bolts but they hadn't been fixed to the ground properly.

'It's a big chunk of metal and it was really heavy,' Ms Cowbourne added.

The first pillar in Utah was originally spotted in 2020 by state wildlife officials who were helping to count bighorn sheep from a helicopter. When the structure suddenly vanished, many thought it was the work of aliens.

However, a photographer revealed later that he had seen four men remove the pillar from the remote area of red rock in Spanish Valley, Utah.

Two weeks after the Utah pillar was discovered, another mysterious monolith, this one 13ft tall, appeared on Batca Doamnei Hill in Romania.

It is not known where there monuments are coming from but some have guesses it is a tribute to 2001: A Space Odyssey.

In the book by Arthur C Clarke, a monolith appears on Earth and gives wisdom to a group of apes.