David McCallum:
The Man from UNCLE
The Invisible Man
Sapphire and Steel
Good one! Though I'd go with NCIS since INVISIBLE MAN was a flop that only lasted one season. Not exactly iconic!
Well, I've never even heard of NCIS, let alone seen it, whereas The Invisible Man is something I well remember from childhood, and it's been repeated loads of times. Maybe it's more popular/well known in Britain? It was after all a prime time show on BBC1.