The 02 prefix for a phone number is, along with the 01 prefix, a Subscriber Trunk Dialling (STD) code; otherwise known as an area code or dialling code. First introduced in 1958, the area code allows a caller to call another telephone directly, regardless of it’s location and without the need for a manual telephone operator.
The process of rolling out area codes was completed in 1979, negating the need for telephone exchanges.
Between 1958 and 1995, geographic area codes gradually evolved. Initially, they used the first 2 letters of a place name as found on a telephone. These 2 digits would follow the number 0. For example, Bournemouth would have the area code 0202 (0BO2), with the letter O becoming a zero. Over the years, the format changed as more and more phone numbers were required. Following a period of time with area codes beginning 00 and 01, the biggest change was seen on 16th April 1995.
Known as ‘PhONEday’, this event changed geographic area codes and some phone numbers. Following PhONEday, all geographic codes began with the prefix 01. This enabled the prefixes 02-09 to be reserved for non-geographic, mobile and premium rate calls. Further changes were rolled out over the following years, specifically allocating the 07 prefix to mobile numbers and the 08 prefix to either free phone or premium rate lines depending on the digits following. All of these changes allowed the space to allow new geographic area codes beginning with the 02 prefix.
In the early 2000s, the Big Number Change had achieved it’s desired outcome of increasing spare phone number capacity and reducing consumer confusion regarding the understanding of phone number prefixes. Now, the 02 prefix was to be only used as a geographic area code. The 02 prefix enabled the amalgamation of inner and outer London (previously 017 and 018) into the area code 020. There are 4 other cities within the UK that use the 02 area code. These are:
Portsmouth (023) 92
Southampton (023) 80
Coventry (024) 76
Cardiff (029) 20
The prefix 028 is used for Northern Ireland.
As a result of the Big Number Change, 02 numbers are now used exclusively for landlines in residential properties and businesses. Whilst calls to these numbers can be diverted across the country, to mobile phones or overseas; the cost of the call to the consumer remains the same, as defined by their phone plan under ‘local or ‘geographic calls.