Finding a location from an area code

Telephone area codes are all associated with specific areas and are usually a good indication of a telephone's location. However, there are exceptions.

If you see a number with a familiar area code in an advert, online or on your phone's Caller Display screen, it is worth remembering that:

There is no guarantee that a number with a particular local area code is linked to a physical location in the associated area.
Incorrect and misleading numbers can be displayed through the Caller ID service, either through errors or deliberately.

Origins of geographically-based numbering

In the days when a country-wide UK telephone numbering plan was first being developed, technological limitations effectively forced a geographically-based approach to be taken.

Individual telephones were connected via a dispersed network of thousands of different telephone exchanges, with calls directed around the country by primitive electro-mechanical equipment. Such systems had no computing ability and relied on a structured, hierarchical numbering plan that corresponded with the underlying physical network.

One element of the numbering scheme was geographically-specific dialling codes. A simplified system of area codes has remained in place for landlines to this day and, as recently as the 1990s, it was almost certain that a phone number that began with a given area code was for a telephone line connected to an exchange in that area.

The situation today

While the majority of standard home and small business phone lines still broadly follow the traditional local numbering patterns, there are no longer any guarantees.

There are several reasons why area codes aren't as reliable an indicator of a telephone's location as they used to be, largely related to the development of new and more flexible communications technology.

Migration to fibre network

Traditional analogue phone lines delivered over copper wires are being progressively withdrawn in the UK. The replacement fibre-based networks do not rely on the same local telephone exchanges and telephone services are delivered as a virtual, digital service over the fibre network instead of as a dedicated wired circuit. Phone companies are generally choosing to follow the traditional layout of area codes when issuing numbers, but the physical association with a specific local telephone exchange that effectively guaranteed which area code a customer would be allocated no longer exists.

Internet calling services

In addition to the replacement of traditional phone lines with digital services, a wide range of other public Voice Over Internet Protocol phone services such as Skype allow telephone calls to be made over the Internet, instead of the traditional phone network. By their very nature, such services don't have a specific physical location – they can be used anywhere in the world.

In 2004, regulator Ofcom decided to allow providers of such services to make use of normal geographical landline numbers as well as the dedicated range of VOIP numbers starting with 056.

Large numbers of home and business users have since been issued with landline numbers for their VOIP phone services and these are largely indistinguishable from standard landline phone numbers. In most cases, people will choose an area code local to where they live – but they can then make and receive calls anywhere in the world regardless of where their number appears to belong to.

Virtual numbers for business

Pretty much anybody can buy a 'virtual' number for any area code nowadays. These be used to forward incoming calls to whatever location the number's owner chooses. For example, a business could buy a virtual number in a specific area to give the appearance of being locally based, with incoming calls actually being answered elsewhere in the UK or even in another country.

Landline numbers for mobile phones

Many mobile phone companies now offer customers the opportunity to have a local landline number for their mobile phone instead of a conventional mobile number starting with 07. They're particularly popular with small businesses and self-employed people who answer most of their calls on the move but prefer to advertise a landline number as a way of projecting a permanent, reliable and local image.

Private networks

Large organisations may have their own private telephone and data networks that cover large parts of the country. Blocks of standard landline numbers are often used to give 'direct dial' access from the public phone network to some or all of the telephone extensions on the private network, without necessarily following the same patterns as standard phone lines.

As an example, an organisation operating nationwide might obtain a single block of phone numbers from the area code covering its head office, then use these numbers at its sites across the country. This is easier and more flexible than obtaining separate local numbers for every single location it operates from.

Caller Display accuracy

Many people have come to rely on Caller Display screens or the 1471 Caller ID service as a way of identifying callers. However, numbers given by the Caller ID service are not guaranteed to be accurate in every case and should not be relied on as a way of verifying a caller's identity.

Firstly, most phone companies allow business users to choose the numbers they present through Caller ID when making an outbound call. It is quite possible for a business to display a UK local number they own, even if the call in question was actually made from the other side of the world.

Secondly, the Caller ID system is not particularly secure. It is relatively easy for individuals or businesses to display false numbers that they do not actually own. For example, fraudsters will often display numbers that look like legitimate, local numbers to appear more trustworthy – but the numbers in question either do not exist or belong to somebody else entirely.

Call charges

One thing that has stayed the same is the way calls to landline numbers are charged. Regardless of whether the number you are dialling is a normal local landline, or a virtual number that's been forwarded to the other side of the world, you will always pay just the standard charge for the type of number that you dialled. Any extra costs relating to forwarding the call to a remote location are paid by the organisation you are calling.

All UK phone numbers starting 01, 02 and 03 are normally charged at normal landline rates. The only notable exceptions are the area codes 01481, 01534 and 01624 for the Channel Islands and the Isle of Man, which are sometimes charged at a higher rate.