Trivia: If you watch throughout the entire series when Brian Potter calls people on their mobile phone. The display name is IRONSIDE. This is actually a reference to an American detective who was in a wheelchair, played by Raymond Burr.
Trivia: There are a lot of running jokes that Peter Kay uses, if you have seen his two live shows then you will have heard 'Garlic bread?' and 'Cheese cake?' in the first episode of series one they use the same joke for 'Head sets?' also the 'I said ping pong balls, not King Kong's balls.' is used in series two, as well as Kay's second live show.
Trivia: Brian Potter is played by Peter Kay. Peter also plays Max, the doorman and the fire detective in Series 1.
Trivia: Spencer can be seen throughout both series. He plays the unknown DJ in series 1, episode 1, and later as part of the drama group in series 1, episodes 4-6. He then, of course, plays barman Spencer throughout series 2.
Answer: Yes it is PK - the characters he plays are Brian, Max, Keith Lard and indeed the voice of the radio. you can hear him on the radio a few times throughout the series.