Murphy's Law

9pm, BBC1

Look at the synopsis of this returning cop series and you might think that in the bowels of the BBC drama department there is a machine called something like the Computer Rapid Assisted Playwriter.

Into this, the Beeb simply lobs a few hackneyed plot ideas and it does the rest. For example, give it a list of ingredients such as "undercover detective", "maverick", "resents authority", "serial killer" and "prostitutes". Then - hey presto! - before you can say "haven't I seen all this before?", the machine spits out the script for tonight's Murphy's Law.

Fortunately for viewers, though, there is still the human element. And it is that - in the shape of star James Nesbitt - which lifts this above the humdrum. He plays the usual charismatic Irish chancer character that he does so well, and makes Tommy Murphy a watchable figure (though you wouldn't want to work with him). Tonight, Murphy disguises himself as a homeless street-dweller to investigate a string of killings linked to a hostel.

Anthony Sher guest-stars as a lead actor at the local theatre - the sort of role which, frankly, he could play in his sleep.