Numbers beginning 01 and 02 in the United Kingdom are allocated for standard geographical use. They are usually referred to as 'area codes', 'dialling codes', or 'std codes'.
They always contain nine or ten digits, after the initial "0", or "trunk code". So, including the initial "0", they are ten or eleven digits long. The part of the number after the first "0" is called the "subscriber number".
A browsable list of geographical numbers can be found in the area code list.
There are four main formats for numbers beginning 01 and 02:
|(01xxx) xxxxxx||This is the most common type of area code.
It is know as 4+6 format, because it consists of a four digit area code (after the "0"), followed by a six-digit subsriber number.
|(01xxx) xxxxx||This format, known as 4+5, is used by a smaller number of areas than the 4+6 format.|
These area codes always have subscriber numbers that are seven digits long. They are known as the 3+7 format, and fall into two groups:
|(01x1) xxx xxxx||This format consists of a three-digit code matching the pattern 1x1 (after the initial "0"), followed by a seven-digit subscriber number. It is used by the following areas:|
|(011x) xxx xxxx||This format consists of a three-digit code matching the pattern 11x (after the initial "0"), followed by a seven-digit subscriber number. It format is used by the following areas:|
These area codes always begin 02. Their subscriber numbers are always 8 digits long.
Consequently, they are known as the 2+8 format ("0", followed by 2 digits, followed by 8 digits).
02 area codes are often misrepresented as being more than 3 digits, for example 0207, but the actual code is 020, and the 7 is actually part of the eight-digit subscriber number.
These short area codes are also know as "wide area codes".
|(02x) xxxx xxxx|
These area codes share their first four digits with four digit area codes, then have an extra digit added to the end of the code. The code is then followed by a subscriber number which is four or five digits long.
Consequently, this number format is known as 5+5 or 5+4, depending on the length of the subscriber number.
The full list of these area codes is as follows: