London postal district

The London postal district is the area in England, currently of 241 square miles, to which mail addressed to the LONDON post town is delivered. The area was initially devised in 1856 and throughout its history has been subject to periodic reorganisation, contraction and division into increasingly smaller postal units. It was integrated into the national postcode system of the United Kingdom during the early 1970s and now corresponds to the N, NW, SW, SE, W, WC, E and EC postcode areas.
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