It was around this point that Blaise was drafted in to the Port Authority building where he was to remain holed up for the duration.

He was part of a group of environmental team who provided advice to the at-sea and shoreline response. “At the time the environmental advisers have far less influence than they do now,” he says.

Dispersants are sprayed to break up the oil....etc

“We certainly couldn't tell people what to do. Advice was as far as it would go. “We certainly influenced where dispersants were used.  It was the biggest use of dispersants in UK history. A total of 446 tonnes of the stuff, sprayed from seven Dakotas and a couple of Hercules.” The use of dispersants is not without controversy. “They break up the oil so it’s diluted quickly and more easily degradable. Most of the oil magically disappears. It hasn’t gone, it’s just that you can’t see it. "They are effective when used correctly and though they are toxic, they are not permitted to be more toxic when mixed with oil than oil is alone.

"It is important to spray oil before it spreads on the sea surface and stop it reaching sensitive places. It's not an easy balance. No one would spray dispersant without good cause, only when it's trying to make a bad situation less bad Back at the salvage operation things were taking on a depressingly familiar pattern. One of the biggest in the world was drafted in to help but the situation did not get any better. Time and again they would temporarily hold the Sea Empress before she broke free and grounded once more.

Soldiers help with logistics: The area has a long history of military connections

The weather continued to play havoc and on reports of sinister noises on board, the ship would be evacuated yet again, amid fears it would breakup and explode. At one stage nearby people in homes were told to leave as the danger from oil fumes escalated. The harbour master later said there was a brief discussion about the possibility of “bombing the thing, and setting light to it”. “We couldn't control it, and oil was pouring out so what else could we do?,” he said. "It was done with the Torrey Canyon in 1967, so it was not something we'd just invented in desperation." By this stage only a comparatively small amount of oil had spilled around 10,000 tonnes. According to the Marine Accident Investigation Branch the vast majority of Sea Empress’ oil cargo - approximately 120,000 tonnes - was still on board. But that was about to change. On Tuesday morning, salvors reported several grinding noises throughout the vessel which was lodged on rocks. More worryingly, “significant losses of oil were observed”. A total of 22 TV and 21 radio broadcasts were made to UK stations alone that day, confirming everyone’s gravest fears. The nadir of the week-long battle was reached - around half of the oil on board began haemorrhaging its vile black cargo into the sea.

Oil still gushing from the Sea Empress after it was finally moored

Finally, on the evening of Wednesday February 21, nearly a week after she first struck rocks, with 13 tugs in place, the Sea Empress was finally floated and brought into the port. The vessel may have been moored but she was still leaking oil. Back on the beaches, there was hell to pay. Locals channelled their upset raising money for wildlife charities, donating towels and washing-up liquid at designated collection centres.

Children prepare for a candle-lit vigil. The mayor of Tenby said it was important to explain to them what had happened "so nobody forgets".

Schools counselled children who had witnessed the violation of their playground beaches and the pitiful site of oil-smothered birds frantically trying in vain to escape. The community defied orders to stay off beaches and mucked in just to feel like they were “doing something”. Some hand-scrubbed rocks while others formed human chains to shift some 20,000 tonnes bags of waste bound for nearby oil refineries or landfill.

Human chains help shift some of the 20,000 tonnes of liquid waste which was dealt with at the Texaco oil refinery

And in true British style, the WI and the WRVS stepped in with a network of refreshment sites. “The clean-up operation on shore continued for almost two years,” Blaise says.

Public meeting with politicians. Locals say seeing pictures or TV footage is nothing compared to witnessing an "unthinkable tragedy"

“The initial cleaning was brilliant and got beaches in someway ready for the influx of tourists for the Easter holidays. But the secondary phase would last a bit longer. "For example in the following October, we had the mother of all storms. “We turned up at work Martin’s Haven one morning to be greeted with that familiar smell. "A couple of hundred tonnes of oil which had been locked in cobble beaches over the summer was floating in the bay. "There were things happening like that all over the place on a smaller scale.”

The 120-mile stretch of coastline directly affected by the spill

So 20 years on what is the reality of the long-term impact of the Sea Empress oil disaster? A Countryside Council of Wales report published in 2006, 10 years after the spill, makes for incredible reading. It states:  The study has found that almost all known impacts to wildlife and marine and coastal habitats from the Sea Empress oil spill had disappeared within five years, leaving very few tangible reminders of its occurrence.” This is mainly down to three things: inclement weather, time of year, type of oil. “With oil spills it’s not just about the quantity but the type of oil spilled,” Blaise says. “North Sea crude oil is relatively light oil and runny. You can wave goodbye to at least third of it into the atmosphere within hours." It was estimated that between 35% to 45% of the oil evaporated and between 45% to 59% was dispersed by a combination of waves, tide and chemical. "Chemical dispersants worked well on it and once dispersed into the water, Pembrokeshire's strong tides continued doing their job and exposed it to all the bacteria who will break it down.

3,495 birds died, 3,428 cleaned. Between 61% and 63% of guillemots recovered were cleaned and released but just 1% were still alive a year on

“The birds took a real hammering. Birds always do and that was awful. But the time of year the spill happened helped minimise things. "Many of the birds were out at sea where they overwinter If it had been breeding season it would have been a very different story. "Despite short-term causalities, bird populations recovered within two or three years.

A grey seal in Pembrokeshire. The area has an estimated population of 5,000

“There was no evidence of impact on seals, otters or even horseshoe bats, which hang out in sea caves," Blaise adds. "And even with the most sensitive places like salt marshes, impacts could not be detected after 2002.” Blaise says recent hydrocarbon analysis of sediment from Milford Haven – effectively a 'fingerprint' analysis of oil compounds which showed no trace of Sea Empress cargo. “There’s no doubt the weather played its part in the clean-up, ironic when you think it caused so many problem for the salvage operation," he adds. "But it did help break up the oil.

Blaise says it is impossible to know how much of the recovery was down to the use of dispersant