Postcode History

Ever wondered how or why postcodes started? The following tale provides an overview of why and when the Postcode system was introduced.

In the mid-19th century, central London postal districts were divided between East Central (EC) and West Central (WC); whilst the perimeter of inner London was split into N, NW, NE, S, SW, SE, W, and E. This first system of ten London postal districts was devised by Sir Rowland Hill and introduced in 1857 and 1858. S and NE were later dropped and are now used for Sheffield and Newcastle. The numbered subdivisions (W1, W2 etc) were a war-time measure and date from 1917. The 1917 subdivisions remain important, because they form the first part of the two-part modern postcode (so N1 1AA is an address in the old N1 district), and because they continue to be used by Londoners to refer to their districts.

Automated Sorting

In the late 1950's, the Post Office experimented with electromechanical sorting machines. These devices would present an envelope to an operator, who would press a button indicating which bin to sort the letter into. Postcodes were suggested to increase the efficiency of this process, by removing the need for the sorter to remember the correct sorting for as many places.

Testing the System

In January 1959 the Post Office analysed the results of a survey on public attitudes towards the use of postal codes. The next step would be choosing a town in which to experiment with coded addresses. The envisaged format was to be a six character alphanumeric code with three letters designating the geographical area and three numbers to identify the individual address. On 28 July Ernest Marples, the Postmaster General, announced that Norwich had been selected, and that each of the 150,000 private and business addresses would receive a code by October. Norwich had been selected as it already had eight automatic mail sorting machines in use.

When this modern postcode system was introduced for London in 1960s, the numerals were added such that the areas nearest central London were allocated the number 1 (W1, SW1, etc.). Afterwards, numbers were allocated alphabetically, not by geography, and with complete disregard to the boundaries of London’s boroughs.

National Roll Out

In October 1965 it was confirmed that postal coding was to be extended to the rest of the country in the "next few years". On 1 May 1967 post codes were introduced in Croydon. The codes for central Croydon started with the letters CRO, and those of the surrounding post towns with CR2, CR3 and CR4. This was to be the beginning of a ten year plan, costing an estimated £24 million. Within two years it was expected that coding would be used in Aberdeen, Belfast, Brighton, Bristol, Bromley, Cardiff, Coventry, Manchester, Newcastle upon Tyne, Newport, Reading, Sheffield, Southampton and the western district of London. By 1967 codes had been introduced to Aberdeen, Southampton, Brighton and Derby. In 1970 codes were introduced to the Western and North West London areas. In December 1970 Christmas mail was franked with the message "Remember to use the Postcode", although codes were only used to sort mail in a handful of sorting offices.

During 1971 occupants of addresses began to receive notification of their postcode. Asked in the House of Commons about the completion of the coding exercise, the Postmaster General, Sir John Eden stated it was expected to be completed during 1972.

A Postcoded UK

The scheme was finalised in 1974 when Norwich was completely re-coded but the scheme tested in Croydon was sufficiently close to the final design for it to be retained. Newport was originally allocated NPT, in a similar way to Norwich and Croydon, with the surrounding towns allocated NP1-NP8. This lasted into the mid 1980s when for operational reasons it was recoded.