There are 37 pre-defined map sheets covering the UK at Sector level displaying all of the first part of the Postcode and the first number of the second part, or Inward Code, at a scale of an inch to 2.4 miles. The Sector maps include all of the Postcode changes in the most recent Royal Mail Postcode Update R45 (February 2008). Area, District and Sector boundaries and numbers/letters are shown in red with County and Unitary Authority boundaries presented in green. The map base shows motorways, primary, ‘A’ and down to unclassified roads with conurbation shapes and city plan insets showing street level detail for major cities.