A fifth steel monolith shaped like a giant Toblerone has been spotted on a Welsh hill.

Locals in Hay-on-Wye spotted the ten-foot-tall block of steel, resembling the distinctive shape of the chocolate bar, on Hay Bluff near the Powys town at the weekend.

The sighting follows a string of similar reports across the UK, with multiple monoliths sighted in 2020, including one at Compton Beach on the Isle of Wight and the Merry Maidens stone circle in Cornwall which attracted hundreds of TikTokers and Instagrammers.

These previous findings have prompted speculation on social media that the structures could be the work of aliens.

However, others have quashed those rumours, instead suggesting the monolith is simply an elaborate piece of undercover artwork.

A steel monolith shaped like a giant Toblerone bar has been spotted near Hay-on-Wye in Wales

The ten-foot steel block resembling the shape of the famous chocolate bar was seen on Hay Bluff

While some speculated that the structure could be the work of aliens, others said it was an elaborate piece of artwork

Richard Haynes, who took pH๏τographs of the latest sighting while running on Hay Bluff, told WalesOnline: ‘I went off towards Hay Bluff towards where the trig point is and I looked over to my right.

‘I thought it looked a bit bizarre and might be a scientific media research thing collecting rainwater.

‘But then realised it was way too tall and strange for that.

‘Then I went up to it and it was about 10-foot-tall at least and triangular, definitely stainless steel.

‘It was hollow and I imagine pretty light.

‘Light enough for two people to carry it up and plant it in the ground.’

Mr Haynes said he frequently ran the route and had never seen the monolith before, while a friend who visited the spot two weeks ago said it wasn’t there at that time.

A large silver structure was seen on top of Glastonbury Tor in 2020 – an ancient hill linked to King Arthur and Celtic mythology

A view of a metal monolith on Zamkova Hora hill in Kiev, Ukraine. Some media outlets have suggested that the monolith is likely an advertisement for a new Ukrainian postal operator

‘I did notice on Google that it’s popped up fairly recently and from what I can gather it disappears after a couple of days,’ he added.

In 2020, a similar monolith was spotted on the Isle of Wight, prompting speculation that it was the work of aliens.

Peter Hudd, a prisoner officer on the island who lives in Ryde, said at the time: ‘My friend Tara thought it was aliens, and other people were saying the same, but I don’t think so.

‘I think someone has done it as a stunt. I believe in aliens too, but not to the extent that they would plonk this big mirror thing on a beach overnight.’

The moost recent sighting has also prompted some criticism.

Despite looking neat and attracting social media attention, some complain that the structures are tacky, aren’t funny, and damage the environment.

Mr Haynes explained: ‘I don’t know about that, but it’s clear someone would have had to have dug a large hole to get it in the ground.’

Monoliths have been sighted in various places across Europe, including at least four other examples in the UK.

Another monolith was spotted on Compton beach on the Isle of Wight in 2020

Britain’s fourth monolith appeared in the middle of one of Britain’s most ancient stone circles

In December 2020, one was spotted on top of Zamkova Hora hill in the Ukrainian capital Kiev, with some suggesting it was an advertisement for a new postal operator.

A silver monolith appeared at Glastonbury Tor in the same month, but was felled by a gust of wind.

Another was found at the centre of the Merry Maidens stone circle in St Buryan, Cornwall.

And beachgoers on the Isle of Wight were stunned to find a mysterious monolith on Compton beach.