From 1844, the Maltese Cross obliterators were replaced by several series of barred numeral obliterators that gave a coded indication of the place of posting by means of the number allocated to the office. In England and Wales the first day of use seems to have been 1st May 1844, with a more gradual introduction in the Scottish and Irish offices in June.

These numbers initially appeared in single numeral cancellations, and later in the "duplex" cancellations which combined a datestamp and an obliterator. Most of these had been superseded by dated stamps by the early 20th century. However, the office numbers were used in instructional and surcharge markings into the 1960s -- there are even a few more modern handstamps that use them.

The obliterator types were distinguished by their shape as follows:

  1. England and Wales provincial -- oval shaped
  2. Scotland -- rectangular shaped
  3. Ireland -- diamond shaped
  4. London Districts -- oval with number in circle
  5. London Inland Section -- oval with number in diamond

& Wales
Scotland Ireland London
Inland Section

Each of the five series of barred cancels used the same number sequence (occasionally with some numbers omitted to avoid possible confusion). The original "1844" numbers were allocated alphabetically to Post Towns, but sub-offices were allocated numbers immediately after their parent office, so even that initial sequence is not entirely ordered! For example, in the original England and Wales series 3 was Abingdon and 5 was Accrington, but 4 was Wantage, which was under Abingdon until 1855. This series ran from 1 (Abergavenny) to 936 (Whitwell, Yorkshire), although the alphabetic sequence ended at 930 (York). The range was greatly extended as time went on. Numbers were frequently reallocated to a different office when the original one closed or was downgraded in status, sometimes several times, and sub-offices might use the same number with or without a code letter.

In the listings here, the offices are listed in numeric order, together with the county, and in the England and Wales list the approximate date that the office was allocated that number (as taken from various Post Office listings). If more than one office is listed (other than sub-offices of the same head office), it means that the number was reallocated. If a range of dates is listed, they represent the first and last official lists in which the allocation of the number to that office appears.