Old telephone area codes with letters UK: direct dialling
The 1950s saw the beginnings of a system by which callers no longer had to go through an operator to connect to a phone outside their local area; they could get through directly from their own phones with a new system called Subscriber Trunk Dialling.
Subscriber Trunk Dialling (STD)
Subscriber Trunk Dialling (STD for short) required every phone to have a letter code for its local area telephone exchange as well as its own local numerical number. It was still possible to get through to an operator, but by dialling 100 rather than the old-style O, for which there was no charge.
The process of dialling is explained on a separate page.
Subscriber Trunk Dialling (STD) was introduced in 1958 and completed in 1979.
Area codes with letters not numbers: early STD codes
There was a logic to area codes being letters rather than all numbers, in that they were the first three letters of the name of a local area. Our family lived in Edgware on the outskirts of London where the code was EDG, but so as not to overload the system, we were allocated STO which stood for Stonegrove, an area on the outskirts of Edgware. So our telephone number was STO 9804. Yes, it was still called a 'telephone number' even though it contained letters.
How telephone numbers were spoken
These old phone numbers were always spoken with the full name of the area code. So, with our STO 9804 telephone number, we announced who we were when we answered our phone, by saying, "Stonegrove 9804", not STO 9804. It was considered very bad form just to say "Hello". How times have changed!
First areas to have letters in their phone numbers
In the middle of the 20th century, only telephones in the wider areas of London, Birmingham, Edinburgh - and from the early 1950s onwards - Glasgow, Liverpool and Manchester had letters on their dials. Elsewhere, even the automatic telephones just had numbers. When dialling a city number from a rural area you still had to go through the operator by dialling O.
Directories of the heads of households on STD were supplied free of charge to those households and to public phone boxes. These were huge tomes, even though the print was tiny and the paper flimsy. A single book was out of the question because there were so many telephone numbers. So the directories came in several books. I remember that the first one was A-D but I can't remember the others. Inside, heads of household contributors were listed by their surname and the initial of their given name(s) followed with their address and telephone number.
The first photo below gives an indication of the size of telephone directories. Ours were kept on a shelf under the telephone table. They were updated regularly, but I can't remember how frequently.
A separate directory with a yellow cover gave business telephone numbers. Everyone called it the 'Yellow Pages'.
As another indication of the size and thickness of telephone directories, it was a typical strong-man display at fairs to demonstrate that he could manage to tear one apart. Visitors were invited to have a go, but only a very small few could manage it.
Telephone directories didn't last long in telephone boxes as people took them for various reasons, but there was a display of area codes mounted on the wall of each box. One is shown in the next photo. It enlarges to a legible size on tap/click, but there is also a transcription below.
Note the instruction for users to dial 100, rather than O for 'assistance'.
London area text-based telephone area codes
Some areas on the outskirts had a code which did not readily indicate the area concerned and could not necessarily be pronounced as a word. For example for Orpington you had to dial MX followed by the number. If you are interested in more in the list, magnify the above image to a legible size.
All-number telephone numbers
As more and more people went on the phone, more numbers were needed and it was decided to change area codes from letters to numbers. Then more numbers could easily be added at any stage by putting an extra digit in front of the original numbers.
Most people I knew were irritated rather than impressed by the change. For a start, telephone numbers with letters were much easier to remember than all-number ones. Also people had invested in printed headed writing paper showing their address and telephone number which was now out of date. Some people decided to buy new showing the all-number phone number, only to find that after a very short time, the new phone number was again out of date as more digits were added.