Behind the trailer are miles of agricultural land sloping gently to the Pembrokeshire coastline and one of the most beautiful, unspoilt parts of Britain. Inland lies the Trecwn valley, site of a heated and increasingly vocal battle between villagers and industry.
The details of this dispute are simple. Omega Pacific, the company which two years ago bought the site of a former arms dump from the MoD, has proposed storing low-grade nuclear waste in the tunnels that run into the hillside. The villagers, fearful of leaks, disasters and leukaemia, are outraged.
The dispute centred on the tiny West Wales village highlights the eternal dilemma for Britain's nuclear industry: how and where to store radioactive waste. A House of Lords select committee is due to report later this year on what it believes is the way forward for an industry whose benefits most people appreciate but whose leftovers nobody wants.
A report recently compiled by the industry watchdog, the Nuclear Installations Inspectorate, said that half of the 70,000 cubic tonnes of waste currently stored in Britain's 22 sites was in danger of leaking. It added that an extra 20 sites needed to be found within two decades.
Even the locals in Trecwn and the neighbouring communities admit that "they have to put it somewhere". The point is, of course, that they do not want it in their valley.
"People are horrified. We are only a small village but if there is any contamination we will be the first to suffer," said Pat Stevens, a campaigner and member of the community council. "Why have they got to put it here? They think `Oh put it out in the country - they're all thick there'. But we are not yokels."
In a show of their feelings, a group of 15 locals will today travel to the Cheshire home of Alan Parker, co-owner of Omega Pacific. There they will deliver to Mr Parker's neighbours tourism brochures showing the splendours of Pembrokeshire, annotated in the campaigners' own handwriting with Omega's proposals.
"We want to show them our beautiful countryside and tell them that Mr Parker wants to dump nuclear waste here. How does he think this will affect tourism?" said Andrew Clemence, Trecwn's vet and chairman of the Pembrokeshire Anti-Nuclear Alliance.
The coalition, which has also put its case to the Welsh Secretary, Alun Michael, lists the dangers of using the site as a waste dump. It points to the streams that run through the valley and join the local water source, the fact that no geological surveys of the valleys exist, and Omega's lack of expertise with nuclear material. They also complain that the company has been secretive - refusing to come to public meetings on the issue - and that the affair has slashed the value of local housing.
"We were within a week of signing the papers on our farm when all this blew up," said Chris and Toni Westmacott, who farm 350 head of sheep on the hills above the valley. "Then the people said they wanted a written guarantee that there would be no nuclear dumping on the site. What are we supposed to do about that? It means we are stuck here."
Omega Pacific offers no guarantees, but it is quick to point out that it has not made any firm proposals to store nuclear waste. All it has done, explained one of its directors, Lawson Stebbings, is to commission a survey which showed the site could be used and then passed this on to the Lords select committee.
But why bother if the company does not intend to go ahead with the plans? The company points to the NSD report's call for extra facilities. "Omega believe that the use of Trecwn would offer an immediate solution and the safest and most environmentally sound way of managing a portion of the UK's ... nuclear waste," it said in a statement.
Mr Stebbings added: "The facility offers a serious, credible, safe and immediate solution as an interim storage facility. This would allow time for further scientific advance in the field of nuclear waste treatment and help prevent what may be a disaster waiting to happen."
The company admits it does not have the expertise to store the waste but would lease the site to a company which did. In the meantime it will go on with its original plans to use the site to refurbish jet engines for the aviation arm of its business.
But none of this convinces the villagers. "We don't really know the full story," said Stuart Avery, who lives a few hundred yards from the site with his wife and children. "We only hear what they want us to."
Or as Alan Prichard, cattle farmer and owner of the black and yellow hoarding, puts it: "No one knows what sort of waste they want to put there or how long for. This campaign is not just about the short-term. It's for future generations."