I saw them ages ago too. Really great series, one of the best detective TV shows there has ever been. Helen Mirren is fantastic and the stories are really involved. I remember someone lending my mum and dad the videos of Prime Suspect 1 and 2. We watched them in one sitting! 1 was so good, we immediately put 2 on.
In the TV family tree, if you liked Prime Suspect, you would also very likely enjoy Cracker with Robbie Coltrane. It was remade in the States I believe, though supposedly very poorly. Another branch from Prime Suspect would be more Lynda La Plante stuff, especially Widows, which is about the wives of a gang of robbers sent to prison, who decide to complete their hubbies last job and get the cash!
All this stuff is pretty tough. Fun in one sense, with a dry humour we British do best, but it still feels hard and real. Very highly recommended. Add it to 'my fault' if you wish...