To find constituencies/local authorities for a GB postcode:
1) Enter the full postcode (for example, SO16 4GU) with or without a space and hit 'Go'
2) Then choose which type of constituency within the selected postcode you would like to see a map of.
Postcodes for Northern Ireland are not currently supported.
NOTE: Very occasionally a postcode will straddle two (or more) constituencies. The constituencies returned for a given postcode are those containing the geographical centre or centroid of that postcode.