Labelled map of Royal Mail postcode districts of the M postcode area.
Indicative postcode districts shown in red, post towns shown in grey.
Equirectangular projection with latitude stretching 170%, WGS84 datum.
Geographic limits:

Main 1:114,000 map:
West: 2.536W
East: 2.077W
North: 53.604N
South: 53.334N
Derived from Ordnance Survey OS OpenData.

Postcode district boundaries within Great Britain derived from Voronoi polygons of OS Code-Point Open unit postcode median coordinates (with coastline clipping and minor adjustments to avoid spurious detached polygons).
Great Britain coastline, inland water and urban extent data derived from OS Strategi.
Richardguk