Telephone numbers - the facts and figures
20 August 2009
Telephone numbers are probably not the first thing that spring to mind when you think of important national resources.
But they're vital in keeping communications running smoothly across the UK and one of Ofcom's roles is to ensure they're managed effectively.
We work to ensure that phone numbers are available for homes and businesses, and that they mean something to those who call them.
Last year alone Ofcom allocated 126 million telephone numbers, including 51 million geographic phone numbers (01 and 02) and 75 million non-geographic numbers (08 and 09 numbers).
But there is a limited amount of telephone numbers available and Ofcom continually monitors demand across the country.
We can also take measures to ensure that numbers in certain areas don't run out where demand is high.
How do we allocate numbers?
Ofcom allocates geographic numbers to communications providers, who in turn allocate them to businesses, homes and organisations. We also allocate numbers to mobile operators to give to their new customers.
Businesses and organisations are normally charged a fee for non-geographic numbers (08 and 09 numbers).
Can you take your number with you when moving home?
It depends on where you're moving to and which company provides your telephone service.
Is it (020) 7 or (0207)?
Since 2000 the area dialling code for London has been 020 - although some people mistakenly believe it is actually 0207 or 0208.
However, the 7 or 8 element is actually the first digit of the local number, depending on whether the number had previously been Inner (0171) or Outer (0181) London.
Ofcom allocates hundreds of thousands of new London numbers every year and as result also introduced new (020) 3 numbers in 2005 to meet the growing demand in the capital.
Sometimes it is not possible to move a number from one exchange to another - even though it is in the same area. If you want to keep your old number you should check with your service provider.
There are around 650 area codes in the UK, ranging from the Isle of Wight (01983) in the south to Shetland (01806) in the far north and some are a bit easier to remember than others.
For example, the dialling code for Bedford is 01234 while the newest area code - for Ebbsfleet in Kent - is also relatively easy to recall - 01987.
But do you ever get a missed call on your phone and don't recognise the number?
A new Ofcom tool - which you can access on the front page of this website - could put an end to that confusion by narrowing down which area of the country the call came from.
It contains a list of all the area codes in the UK and you simply type in the number to look for matching locations.
So, for example, if you typed in 01509 you'd find that this is the code for Loughborough.
Sometimes films and TV shows include a shot of a phone number as a part of the story.
A recent episode of Doctor Who flashed up the Timelord's mobile number - 0770 0900 461 - as the Doctor battled to save the world.
Did you know?
Itemised billing was first introduced on a trial basis in parts of Bristol and Bath in 1983
There are almost 77 million mobile subscriptions in the UK - more than the entire population 80 billion texts were sent last year 999 was first introduced in London in 1937.
You can also dial 112 in any EU country to get through to the emergency services but you'd need to ring 21606666 to call an ambulance in Algeria
The red telephone box was designed by Sir Giles Gilbert Scott, who also designed Bankside Power Station which now houses the Tate Modern
London telephone operator Miss Jane Cain was the first voice of the speaking clock in 1936
Comedian Ernie Wise made Britain's first mobile phone call across the Vodafone network in January 1985
And with millions glued to the action, it's a safe bet that dozens - if not hundreds of fans - immediately leapt to their phones to dial the number in question.
But anyone who did ring it would have just heard an automated message informing them the number was not recognised - although they were not charged for the call.
That's because programme makers don't just randomly pick phone numbers out of thin air. Ofcom has a dedicated list of numbers set aside to be used specifically by production companies.
For instance, the mobile numbers between 07700 900000 to 900999 have been set aside for drama purposes.
Mobile companies can't allocate these numbers to customers because of the potential influx of calls should the number be shown in a drama.
We have also reserved blocks of landline numbers in different geographical areas of the UK and programme makers can also use the generic area code 01632 for any areas not covered.