By Nick Parry BBC Wales news website

Protesters occupied the building site during the winter of 1985

It led to peace protests, a long-running High Court battle and cost an estimated �400,000 to complete.

Buried under a car park and used to store paperwork, visitors to the town today would not even know it exists.

As the BBC Wales news website is given a rare look inside, we speak to one campaigner who recalls the controversy.

For most of the 1980s the Cold War, a nuclear stand-off between the former Soviet block on one side and western Europe and the USA on the other, continued.

With the on-going threat of nuclear war the then Conservative Government led by Margaret Thatcher was offering local councils grants of up to 75% to build nuclear shelters.

Clicker here to take a look inside Carmarthen's nuclear bunker In pictures

The decision by the now defunct Carmarthen District Council to build one just off Spilman Street in the town caused a big outcry.

Solicitor Mike Reed was one of 17 peace activists made the subject of a High Court injunction banning them from the site after they tried to occupy it, but said he had no regrets over the protests.

"There was so much opposition from prominent people and local people," he explained.

"It was at the time when people were very concerned about nuclear proliferation.

"It was at the time of the Cold War and these bunkers were being built around the country and there was a fear that it was going to increase the risk of a nuclear war.

"Even Margaret Thatcher got to hear of it - that there was this protest going on 200 miles away that had to be stamped out.

There must be a use but clearly it is such an embarrassment that I don't even think they want to explore it Mike Reed

"It started off with a protest and because they (the old Carmarthen district council) actually started work without planning permission local peace protesters occupied the site and stopped the work.

"They built a 12ft high spiked steel fence around it and they got a security firm with Alsatian dogs. It was very serious stuff.

"It was a fascinating campaign, albeit sad that we did not stop the thing being built."

Events culminated in a demonstration that saw several thousand people form a human chain around the bunker off Spilman Street.

But just after it was completed the Berlin Wall came down and the Soviet Union broke up.

"Shortly after, government policy changed and the Cold War came to an end," added Mr Reed.

"I don't know what the ultimate cost was but the estimate was something like �400,000.

"It's very sad that all that money was spent and it's never been used.