Telephone Charging Rates

As applied by BT

Written by Clive Feather

Last updated 2025-01-03

Introduction

Many telephone companies charge the same prices for calls to all geographic (those beginning 01 and 02) and pseudo-geographic numbers (03). However, that didn't always used to be the case, and some companies still distinguish between "local" and other numbers. This page discusses the meaning of "local" and related terms, at least how they were applied by BT. Much of this page uses the present tense, because the concepts still exist even though they have no practical use.

In my work over the years, I discovered that a lot of people didn't really understand how the phone calls they made were charged. For example, many people believed that a phone call was more expensive if they dialled a number beginning 0. While it is true that all long-distance calls do begin with 0, so do many local calls.

(For those unclear about this concept, it is possible to omit the dialling code if it is the same as your own and begins 01 or 02. So if your phone number begins 020, then you can dial 7222 1234 rather than 020 7222 1234. Furthermore, there used to be a series of "local codes". Thus from 0223 (now 01223) numbers, it was possible to dial 92 instead of 0638 and 93 instead of 0954. Contrary to some people's belief, it made no difference to the cost whether you used the full code or the local code.

Before we start ...

This material has been compiled from various sources. It is correct to the best of my knowledge, but I take no responsibility for any use made of it. This page is not sponsored, supported, or otherwise connected with BT other than through use of publically available BT material.

Some other telephone companies use the same method of charging as BT, or a variation thereon. Others do not. You should contact your telephone company for specific details of how they charge for calls. Furthermore, this material only applies to calls between geographic numbers, and not mobile or personal numbers or other services. For an example of the range of non-geographical numbers, and the different rates that apply, see the Kingston Communications tariff.

I would like to know of any errors in the information presented. The best form of evidence is an extract from a telephone bill. Nearly as good is an extract from the local telephone directory, though these have been known to contain mistakes. In both cases, please email me a scanned-in image or a pointer to an image. I do not consider statements made by BT operators to be evidence; I have far too many examples of when they have given wrong, or even nonsense, answers.

Types of call

The BT charging system has three types of call: local, regional, and national. Local calls are generally cheaper than regional ones, which in turn are cheaper (or sometimes the same price as) national ones. Of course, the cost of a call also varies according to the time of day and the day of the week.

On 1999-10-01 BT made the regional and national rates the same for all calls, and on 2000-12-20 they formally abolished the distinction.

Charge groups

BT divide the United Kingdom into 637 "charge groups", each with a name and a reference number. In theory, each group covers a particular area, and (it is claimed) the boundaries between the groups are regularly adjusted. However, it is not actually necessary to know the boundaries, as it is always possible to tell which charge group a phone belongs to by the first 4, 5, or 6 digits of its number.

Some charge groups cover a single dialling code while others cover more than one, and some dialling codes are split into several groups. For example:

• The Cambridge charge group contains all 01223 numbers.
• The Sheffield charge group contains all 0114 numbers.
• The Bristol charge group contains all 0117 numbers and also all 01275 numbers.
• 0191 numbers are split between three different charge groups:
  • Durham for numbers beginning with 3,
  • Newcastle for numbers beginning with 2, 4, or 6, and
  • Sunderland for numbers beginning with 5.
• 028 numbers are split into a large number of charge groups depending on the first two digits.

Relating call types to charge groups

All calls between numbers in the same charge group are local calls. However, the converse is not true. If two charge groups touch each other, then a call between them is also local. The catch, of course, is determining which charge groups do touch. It ought to be simple to decide, but there are a number of problems. Firstly, BT do not publish maps of charge group boundaries, claiming that there are tens or hundreds of changes each month. Then there are a number of marginal cases. If two charge groups are on the opposite side of a bay or river estuary, there is no easy way to tell if they "touch" or not. Furthermore, sometimes four, rather than three, groups appear to be about to meet at the same place. Sometimes all four are local to each other, and sometimes there is one pair which are not. And finally, there are a number of explicit special cases where calls are made local in order to bind a community together.

While local calls are defined in terms of charge group boundaries, regional and national calls are not. Instead, each charge group is given a location known as its charging point. If two charge groups are not local to each other, it is necessary to determine the distance between their charging points. If this is under 56.4km, calls between them are regional; otherwise they are national. Naturally, BT do not publicise the actual locations of the charging points.

Finally, the Republic of Ireland adds yet another special case. Calls from Great Britain (England, Scotland, and Wales) to the Republic are charged at a special "Irish" rate. But calls from Northern Ireland are charged on the same basis as calls within the UK - a charge group in Northern Ireland may be a local call, a regional call, or a national call to a given charge group in the Republic. In particular, there are cross-border local calls.

Finding your charge group

For more information about the charge group a number is in, and what groups it is local to, find the first few digits in the following list.

00   010  
0110   0111   0112   0113   0114   0115   0116   0117   0118   0119  
0120   0121   0122   0123   0124   0125   0126   0127   0128   0129  
0130   0131   0132   0133   0134   0135   0136   0137   0138   0139  
0140   0141   0142   0143   0144   0145   0146   0147   0148   0149  
0150   0151   0152   0153   0154   0155   0156   0157   0158   0159  
0160   0161   0162   0163   0164   0165   0166   0167   0168   0169  
0170   0171   0172   0173   0174   0175   0176   0177   0178   0179  
0180   0181   0182   0183   0184   0185   0186   0187   0188   0189  
0190   0191   0192   0193   0194   0195   0196   0197   0198   0199  
020 021 022 023 024 025 026 027 028 029
03   04   05   06   07   08   09  

Derivation

Where do these codes come from? More precisely, how were they chosen? Why is Weedon (01327) way before Ashbourne (01335) rather than the numbers being allocated in alphabetical order of town name?

To understand this, it's necessary to start with the original phone technology. Before the days of cable and fibre, all telephones were connected to their local exchange using a pair of wires (many still are). When the handset was on its rest on top of the rest of the telephone, the two wires were connected and the exchange knew the line was not in use. When the user picked up the handset, the lines were disconnected from each other. The handset had a dial on it with 10 holes in it and a finger-stop. Each hole revealed a digit from 1 to 9 then 0 and possibly some letters (see the images near the start of this page). To call another number, the user put their finger in the hole corresponding to the first digit, say 5, then pulled it around the edge of the dial to the finger-stop, rotating the whole dial clockwise. When they took their finger out, the dial would spin back under the influence of a spring, briefly connecting the two wires together five (in this case) times, telling the exchange that the first digit was 5. This process was then repeated for each digit in turn.

The exchange codes were originally derived from the letters associated with the digits on the phone:

The digit after the two letters was allocated roughly in order of importance, starting with 2, then 3, then on to 9, then 0, and last 1. "0" comes after "9" on the dial and generates 10 pulses to the exchange, so it's logical to place it after 9 in order. "1" was discouraged for technical reasons: traditionally, the first section of the wires from the house to the exchange were overhead, so a strong wind could touch the wires together briefly, producing a spurious "1" digit if a number was being dialled. This is also why the number-to-letter mapping starts at 2.

Of course, it wasn't quite this simple. Some pairs of letters had so many places that other names, with other letter pairs that mapped to different digits, were used. Or the third or fourth letter was used instead of the second. Originally "O" was used as the first letter of places (such as Oxford, which was 0OX2 = 0092), but various issues meant that this was forbidden in the 1968 and replacement codes were issued (e.g. Oxford became 0865).

("ring" after a place name indicates a second dialling code for the small exchanges around the outside of the place itself. So "Bristol ring" covers various exchanges outside Bristol itself.)

Director areas

The major cities in the UK had many telephone exchanges within the city and call routing became complicated. These cities were fitted with "director" equipment that split a 7-digit number into an exchange code of 3 digits and a subscriber number of 4 digits. The director equipment converted the first three digits into a route - which could be direct or indirect and which could be changed without renumbering - while it held the remaining four, then sent them to the destination exchange.

The six director areas were each issued a dialling code which was clearly based on the letter system (though this was not officially stated):

Between 1982 and 1988 the 0385 (DUrham 5), 0632 (NEwcastle 2), 0783 (SUnderland 3), and 0894 (TYneside 4) codes were merged into a new 091 ("tYneside 1" or "tyne and Wear 1") dialling code, though this wasn't a director area as such.

In 1990 the London area was running out of usable numbers and so was divided into two separate dialling codes: 071 for inner London and 081 for outer London.

011x numbers

On 1995-04-16 ("phONEday") a "1" was inserted into all geographical telephone numbers (but not others such as premium rate numbers) after the leading zero. This explains why Lydney is now 01LY4 and Glasgow is 01G1. Initially the extra number space was used to move five more areas to 7-digit numbers, allowing more subscribers in those areas. These were:

In 1998 0734 (REading 4) was similarly migrated to 0118.

02x numbers

In 2000 ("the Big Number Change") a new set of 02x dialling codes were introduced, each using 8-digit numbers. Only five of these ten codes (shown in bold) have been used so far, and in three cases only for small areas, but sources report that the idea was to split non-London England into 6 areas allocated in a roughly geographical order, codes allocated using letters for the other three home nations, and a code for the London area:

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