Britain has different length area codes. 020 is London, 0121 is Birmingham, 01234 is Bedford, 015396 is Sedburgh, population 2700.
The local part of the number is 8, 7, 6 or 5 digits accordingly.
I never found this to be a problem. If you're dialing locally from a land line, you usually know the local code. For national or international dialing it doesn't matter.
Occasionally people put the space in the wrong place, like 0207 77777777 for a London number.
> Occasionally people put the space in the wrong place, like 0207 77777777 for a London number
To expand on this, the codes have changed a lot over time. London used to have separate codes for inner and outer London, which at their last iteration were 0171 and 0181. These were replaced in 2000 with (020)7 and (020)8 respectively. At this point it still made sense, if inaccurately, to group the first four numbers. There was also some perceived prestige with having an inner London number.
In 2005 (020)3 was included due to a shortage of numbers and (020)4 for the same reason in 2019. With the portability of numbers and the extra ranges it no longer makes sense to group the first four - and the number of people who want to infer location from a landline number is probably much lower these days anyway.
Actually, London used to have one area code, "01".
Then at some point it was split into inner & outer, and there was endless one-up-manship about whether you had an inner or outer London code. (obviously, inner London was posher)
I believe you -- in the large village where I grew up there was some daft division between having a 5-digit area code for a nearby town rather than the (nearer) large city's 4-digit code, and (along roughly the same lines) having <Town, Countyshire> as your official address rather than <Large city>.
But it seems odd for London, when there are plenty of posh areas in outer London, and run-down areas of inner London. Maybe it was more for businesses to appear 'central'?
This feature of a numbering system is referred to as “open-plan numbering“. In a place with “closed-plan” numbering, all telephone numbers have the same length and format.
It kind of makes sense. You can then have a mix of large and small area codes. A small number of large cities and a larger number of small towns. The problem of course appears when an area starts to grow...
The local part of the number is 8, 7, 6 or 5 digits accordingly.
I never found this to be a problem. If you're dialing locally from a land line, you usually know the local code. For national or international dialing it doesn't matter.
Occasionally people put the space in the wrong place, like 0207 77777777 for a London number.