UK useage.
The police in an area notorius for it's highcrime rate eg Whitechapel in East London,
The Barton Hill area of Bristol,
Bootle in Liverpool, the cornish town of
Bude etc.
So called because said police see themselves as the only thing preventing an out break of anarchy
With
19 muggings,
34 assaults, 4 street fights, 7 car jackings, a rape, a murder and only 6 police the
thin blue line is being streached tonight.