SO postcode area

The SO postcode area, also known as the Southampton postcode area, is a group of 23 postcode districts in England, which are subdivisions of nine post towns. These postcode districts cover south and central Hampshire, including Southampton, Winchester, Alresford, Brockenhurst, Eastleigh, Lymington, Lyndhurst, Romsey and Stockbridge.
The area originally had both single and double-digit postcode districts. From the inception of postcodes in Southampton, 'large users' within the SO1 and SO2 postcode areas (which broadly covered the area of the City of Southampton) were allocated SO9 postcodes. In the early 1990s, a shortage of available postcodes occurred due to increased demand. On 1 December 1993 Royal Mail took the step of dividing each of the existing single-digit districts, the numbers of the new subdivisions containing two digits rather than one. For example, the SO1 and SO2 districts were divided into SO14-19. At the same time, ordinary 'geographical...