Twenty years ago, Pembrokshire was at the heart of one of the worst environmental disasters to hit Britain’s coastline.

The grounding of the 147,000-ton supertanker Sea Empress at the mouth of Milford Haven on that fateful day, Thursday, February 15, 1996, grabbed international headlines as the county faced a pollution nightmare which threatened its economic and environmental future.

A cloud hung over the area’s popular resorts that was almost as dark as the mass of oil that flowed onto the beaches.

Bitterness, sadness, anger and frustration were just a few of the emotions felt by local people looking on helplessly as our beautiful beaches were desecrated before their very eyes.

A mammoth effort from armies of council workmen and volunteers offered hope that Pembrokeshire’s magnificent coastline could be returned to its former glories. And those efforts were rewarded, as evidence of the oil spill horror faded within a few years... although memories still remain.

Here we take a pictorial look at the unforgettable events of 1996 and how the Observer broke the news.

See this week’s Observer or subscribe to our online edition to see the full feature, with news extracts from 1996.