In detail: The Sea Empress disaster

Early on the evening of 15 February, 1996 the Sea Empress, a single hull oil tanker, began to enter the mouth of the Cleddau Estuary on her way to Milford Haven in Pembrokeshire.

Sailing against the outgoing tide, at 2007 GMT she hit rocks in the middle of the channel, holing her below the waterline.

The ship's cargo of 130,000 tonnes of crude North Sea oil started to spill into the sea.