The loudest mouth in the station belongs to DI Grim, whose outbursts are always directed in one of two directions: undermining the uniform branch; or boasting about CID. He is clearly the loudest proponent of taking a hard line with criminals, including endorsing an idea to put a maternity ward within a juvenile detention centre: out of the mum and into the cell!
Derek's inability to put together a solid case and bring in criminals is almost as dumbfounding as his incessant drive for success. More often than not his lack of judgement results in him making an ass of himself and his whole department. Whenever he has 'liaised' with other higher branches – such as 'special branch', Scotland Yard, or the Metropolitan Police – he has not only failed to impress them, but also occasionally brought scorn upon himself.
Almost like a caricature, he is stereotypically the fool who is in a position of authority, and is usually at the root of his own poor 'fate'. The sheer silliness of some of his outbursts make him the antithesis of
Raymond Fowler; and indeed, the two men often butt heads on policing methodology.