The firebug ( Pyrrhocoris apterus ) is very rare in Britain. Only a few colonies are known.
I was alerted to the existence of a colony at Sompting by Graeme Lyons' blog "The Lyons Den" so I took a walk over there today. And there they were!
Not many people in England are familiar with the firebug and I think that they should be described as the "African mask bug". I'm sure you can see why.