Image: street sign “Greville Street E.C.” on Holborn Bars, across Leather Lane from The Argyle pub at 1, Greville Street.
“Most of the information and the list here were provided by John Henley, in answer to a question on the London email list. He extracted the information from a variety of web pages. There is an addition from The Postal Museum, with further details contributed by Philip Huddy.
The origins of the existing UK Postcode go back as far as the middle of the nineteenth century and arose from the rapid growth of London in the earlier years of that century. So rapid was this that the then Post Office could no longer regard the city as a single town from the viewpoint of sorting mail. Thus the division of London into Postal Districts in 1857-8 effectively divided the capital into smaller and semi-independent postal towns. Sir Rowland Hill, the designer of the first stamp and the man who introduced the uniform postal rate for the whole country, carved up London into eight such Districts. These were denoted by letters representing compass points.
The original 10 districts were EC (Eastern Central), WC (Western Central), and then NW, N, NE, E, SE, S, SW, and W. Thereafter, all mail from the rest of the country was sent directly to the appropriate office. According to the Postal History Museum NE was combined with E in 1866, but entries in the Post Office London Suburbs Directories, addresses on old letters, and street name-signs show that it was being used again c1890-1917. S was abolished and divided between SE and SW in 1868. Between 1864 and 1912, cities such as Liverpool, Manchester, Dublin and Sheffield followed this lead, sometimes using numbers alone, without letters.
Towards the end of the nineteenth century in London, then the world’s largest city, the situation became clogged again. Initially as a war-time labour-saving device, a suffix on the Postal District denoting the Sub-District was introduced formally in 1917. The allocation of the numbering was alphabetical. In each district, the sub-district nearest the centre of London was given the number 1. Others were numbered in alphabetical order of the main delivery office in each district. Thus the inner part of Eastern District became E1 whilst Bethnal Green Sub-District became E2 and Bow became E3. Numbers at the end of each alphabetical sequence are later additions. Subsequently the original Postal Districts in London became Areas and the Sub-Districts became full Districts in modern terminology.
Postal “counties” do not coincide with administrative counties, and post code districts do not map exactly onto London boroughs or “villages”.
In some parts of central London the first part of the postcode has an additional letter, e.g. Holborn Library is WC1X 8PA.
EC1 covers the Clerkenwell, Finsbury, Barbican area
EC2 covers the north eastern (Moorgate, Liverpool Street) area of The City
EC3 covers the south eastern (Monument, Aldgate, Fenchurch St, Tower Hill) area of The City
EC4 covers the western (Fleet Street, Temple, Blackfriars, St Paul’s) area of The City
WC1 covers the Bloomsbury & Gray’s Inn area
WC2 covers the Holborn / Strand / Covent Garden area”