I can't remember how I managed to stumble across this series a good many years ago now, but somehow - and I still haven't been able to work out just how - it managed to hook me almost instantly. There is so much subterfuge, nasty, backroom dealings and internal politics going on and plain intrigue that it hardly matters that there's almost no real action in this series. Virtually everything goes on in the offices of the Sandbagger unit and there's not even very much outdoor camera work, so I suspect this series was made on an incredibly cheap budget, but the scripts are good, the plots are believable, the acting is excellent when you consider that these guys are spies who are not meant to betray too much emotion, and the tension is constant. Good British psychological drama.