catj wrote on Jun 6^th, 2009 at 1:13pm:

When I originally wrote that, I was unaware that there's one more format used in twelve places in northern England and the borders.

Langholm (013873), Hornby-with-Farleton (015242), Hawkshead (015394), Grange-over-Sands (015395), Sedbergh (015396), Wigton (016973), Raughton Head (016974), Brampton (016977), Appleby-in-Westmorland (017683), Pooley Bridge (017684), Keswick (017687), Gosforth (019467):

Numbers with the above area codes are written:  (01xxxx)  xxxxx   (5-digit number).

Additionally Brampton has some four-digit local numbers at:  (016977) 2xxx  and  (016977) 3xxx   (4-digit number).

These are known as "Mixed" area codes. I assume that's because these longer area codes overlap with another shorter format, e.g. Dumfries is  (01387) zxxxxx   (where "z" cannot be "3")  and Langholm is  (013873) xxxxx.

Another example is where Lancaster is  (01524) zxxxxx  and  (01524) zxxxx   (where "z" cannot be "2")  and Hornby is  (015242) xxxxx.


There are a small number of entries for these areas already in the database, but they currently display incorrectly.

e.g.  in Keswick (which uses the 017687 area code):

Youth Hostels Association is shown as  01768 772484  but should be  017687 72484.
Dialling 772484 within Keswick connects to Keswick 77248, not the intended Keswick 72484.


e.g.  in Wigton (which uses the 016973 area code):

Lloyds TSB is shown as  01697 343110  but should be  016973 43110.
Dialling 343110 within Wigton connects to Wigton 34311, not the intended Wigton 43110.


Likewise for numbers in Hawkshead, Ambleside, Coniston, Eskdale, Grasmere, Windermere and other places.




catj wrote on Jun 6^th, 2009 at 1:13pm:

The corrected information:

Local numbers can be 4 to 8 digits long.

The area code can be 2 to 5 digits long, after the initial zero.

The total number length is always 9 or 10 digits, after the initial zero.




This UK area code list seems to be accurate:  http://www.telephonenumbers.co.uk/Geographic-Codes/i=2

A detailed list of the "Mixed" area codes is here:  http://www.aa-asterisk.org.uk/index.php/Mixed_areas

Simply, longer local numbers are used where there are more people and shorter local numbers are used where population numbers are low. In order to ensure telephone numbers are of reasonably consistent overall length (total digits for area code and local number), longer local numbers are paired with shorter area codes and vice versa. Most UK numbers have 11 digits including the leading 0. In low population areas, there's a few with only 10 digits including the leading 0.

Ideally, the last few places using 10 digit numbers would add a digit to give a consistent format, but there's no really compelling reason to change local numbers that in some cases have remained unchanged for anything up to 50 years (noted that these places did see the digit "1" added to their area code in 1995).

London needs 8 digit numbers. It would otherwise have to be divided up into multiple area codes. Under the current scheme, number ranges covering about 26 million numbers have been allocated to providers and there are some 54 million numbers free in the (020) area code. London has enough spare number ranges to last at least several decades, if not some time well into the next century.

Brampton uses 4 and 5 digit local numbers because it has less than 5000 active lines. The only reason for a number shortage here would be Ofcom allowing 500 providers to each reserve a block of 1000 numbers they will never actually use.

The rules are not especially complex, with most geographic numbers using 2+8, 3+7 or 4+6 format. A few places using 4+6 format also use 4+5 format. There's also a small number of rural areas using 5+5 format and one of those also uses 5+4 format. NDO numbers use 0+10 format. Non-geographic numbers mostly use 0+10 format, but some 0800 and all 0500 numbers use 0+9 format.

It's a system that has evolved over 50 years or so, and has been altered several times to meet capacity demands. BT made a reasonable job of things. The system was reasonably logical. Oftel and Ofcom have not been as good, as discussed in several other threads last year/earlier this year: http://www.saynoto0870.com/cgi-bin/forum/YaBB.cgi?num=1290685881  and http://www.saynoto0870.com/cgi-bin/forum/YaBB.cgi?num=1289306809

The US system goes the other way. There's a consistent presentation format for numbers but inconsistency in what is actually dialled. In some places an area code covers a whole state. In other places, multiple area codes cover the exact same steet. Depending on where you are, local calls may be dialled with 7 digits or with 10 digits. There may be a choice as to which one to use, or there might be only one format that will work. Long distance dialling will usually require 1+10 format, and it might also be required for calls which are to the local area. As areas have run out of numbers, additional overlay codes have been added rather than extending the length of the numbers.

idb wrote on Oct 22^nd, 2011 at 5:12pm:

This begs the question, what does each "code" signify?

For landline numbers it is the locality and for mobiles it is the network operator. The former is understood, but is it a relic of the bygone days (clockwork exchanges)?

Mobile numbers, for most people, are just 11 digits where the first two are 07.