Blackadder Goes Fo(u)rth has got to be the best. The last episode is also very moving. I'm a great fan, particularly of Melchett and his "outer office". It's a worrying fact that my 8 year old daughter occasionally trots out lines like "Yes, Pratt at the back" or "Oh, Mr Thicko, fancy not knowing that" and so on. The Private Plane episode must have been written with considerable help from Service personnel as the humour is spot on -either that or perhaps we are all stereotyped already!
