An explorer has shared the moment he climbed down into a Cold War Bunker after finding the concrete hatch ‘hiding in plain sight' in the Welsh countryside.

Jay Curtis, 35, was taking a lockdown walk near his home in Clydach, Swansea, in May of last year when he decided to venture down the ladder inside one of the rusted hatches he spotted along the route.

After taking the daring 14-foot climb down Jay discovered the remnants of a declassified nuclear monitoring post from the late 1950s, sharing the results to his Youtube channel Jay Curtis Explores.

In the video Jay, who works as a Broadcaster, can be heard marvelling at the ‘eerie’ underground structure, which was used by Royal Observer Corps volunteers to monitor incoming nuclear strikes during the Cold War.

The explorer gives viewers a short tour of the main observation room where three people would have worked in shifts, taking turns to sleep on the bunk bed.

He also reveals the tiny chemical toilet room, a BT junction box and wiring, and the remains of a hand-cranked water pump used to stop the bunker from filling with water.

‘I spent around half an hour exploring the monitoring room below ground as I had only the light on my smartphone to guide me’, Jay told Jam Press.

‘However, my curiosity was soon replaced with the realisation that I had just 10% battery remaining in a dark concrete bunker where the walls were twelve inches thick and I still had to climb back out with what little light I still had left.’

He added: ‘The clamber down the 14-foot-deep access shaft was probably the scariest part. With the bunker dating back to the 1950’s I had no idea how sturdy the ladder would be but feeling reassured that they were built to withstand a nuclear blast I took each step slow and steady.

‘I’m also not great with small spaces or spiders which did not help descending through the various cobwebs and my inquisitive side really got the better of me so I just had to take a look.’

Jay urged others to look out for the historical hatches, explaining that over 1500 of them had been built ‘between eight and ten miles apart’ across the UK during the Cold War tensions - with many since filled in due to flooding or vandalism.

The bunkers were later declassified and abandoned as late as the early 90s when satellite monitoring technology took over the same tasks, Jay explained.

Jay told Jam Press: ‘I had the biggest surprise to discover that sitting there in plain sight for years was a relic of the Cold War.

‘The feeling below ground was very eerie. You could hear nothing from life above ground, including the shouts from my partner who was yelling to make sure I was ok in the foot of water at the bottom.’

Whilst in the bunker Jay said he had the ‘odd realisation that the once top-secret concrete structure was built for the very real threat of war’ and that anyone left outside of the structure, including the workers' families, ‘faced certain annihilation'.

In the video of the close-to-home adventure, Jay explained how a probe and a pinhole camera on the roof of the bunker would have ‘supplied information on the bombing above ground’, with another device pressed to the wall to measure the ‘pressure of a bomb going off above ground’.

Jay explained how the lighting in the now pitch-black bunker was once supplied by a 12 Volt battery charged by a generator above ground.

During the tour he also pointed out a speaker system mounted to the wall, telling viewers: ‘This gave updates from the government when an attack in this area was imminent, and if that happened, then they would have to reach up to the top sound the alarm, and then close the air vent to avoid any nuclear fallout.’

Concluding the video Jay told viewers: ‘Thankfully the call never came, and in 1991 this bunker, like many others, was shut as technology had moved on.’

The bunker Jay explored has now been sold for a whopping £25,000. Jay hopes it will be cleaned out and restored or redeveloped into ‘holiday accommodation with a difference’.