When we think of oil spills, the images that come to mind may include seabirds coated in black slime, huge iridescent slicks lapping onto shore and armies of wellington-clad cleaners armed with buckets. The spill in the North Sea is different yet may be no less harmful.

A collision between the US-registered oil tanker Stena Immaculate and the Portuguese-flagged cargo ship Solong in the North Sea has left one crew member missing and fires still burning.