Critical Mass

Monroe is sceptical but cautious when a young woman rings Sun Hill and says she thinks her boyfriend, Ben Wallace, may have hidden a bomb in the station. As the relief begin to conduct a search, Carver finds a suspect device hidden in the ceiling of one of the interview rooms, and the bomb squad are called in to assist. As Monroe leads a full evacuation of the station, he and Conway watch from a nearby van as the elite bomb squad officer attempts to defuse the device. The bomb is eventually rendered useless, but the officer is confused as to why there were a number of dead wires loose inside when the bomb was constructed so well - until he realises there could be another bomb elsewhere.
== Characters ==
Ch Insp Derek Conway 
PC Jim Carver 
PC Vicky Hagen
PC Di Worrell
DCI Jack Meadows 
WDC Kerry Holmes 
PC Cass Rickman
PC Dave Quinnan 
Sgt Bob Cryer 
Sgt Matt Boyden 
DC Duncan Lennox 
Insp Andrew Monroe 
PC Reginald Hollis
Sgt June Ackland 
PC George Garfield
PC Gary McCann 
PC Tony Stamp 
== Guest Stars: ==
* PC Discombe-George A. Murphy 
* Ben Wallace-Nick Waring
* Frank Wallace-Nicholas Day 
* Helen Wallace-Maggie Stride 
* Emma Crawford-Kate Steavenson-Payne 
* Jill Palmer-Rebecca Hartley 
* Paul Weston-Tim Faraday 
* Trevor Miller-Ian Peck
* Peter Yates-Leo Dolan
* Carl Maxwell-Thomas Goodridge 
* Mike Best-Dominic Taylor