Posts by janster

The point is that phone numbers aren't just an 11 digit string processed by a database lookup. The digits are processed and interpreted sequentially. For example, (01202) 391234 isn't interpreted in one go: 01202 39 would be enough to route to BT's exchange in Boscombe, where further processing on the rest of the number takes place.

When you start dialling on a landline, the first digit has a special significance and tells the system what to do next:

0 means "this is going to be an area code or international call"

1 means "this will be a short code, like the operator on 100"

2,3,4,5,6,7,8 or 9 means "this will be a local call"

In Bournemouth, you could dial (01202) 234567 as just "234567". As you've started with a "2", the system can easily spot it's a local number and knows to expect 5 more digitis. Remember, there's no "send" or "call" button on a normal landline so the system needs such information to know what length number to expect to identify when you have finished dialling.

Now imagine the number (01202) 020722 is issued. If you dialled 020722 locally, that leading 0 suggests to the system you're making a long distance call and it would just sit there forever waiting for you to dial the next 5 digits.

Likewise, what about (01202) 123456? If you dialled that as simply 123456, you'd be connected to the speaking clock as soon as you'd got as far as dialing "123".

Requiring the area code removes those kinds of clashes.

Of course, it's still a big bodge job. Odds are this will only see us through a few more years before they have to find more numbers for Bournemouth, Brighton, MK, etc. I guess Ofcom would rather dodge the bad press of a futureproof number change and leave somebody else to sort out the inevitable mess ten years down the road!

Sadly, people are too dim to get this.

Cardiff, for example, went from (01222) xxx xxx to (029) xxxx xxxx. All the old 6-digit local numbers got prefixed with a '20' to make them 8 digits in length. e.g. (01222) 872087 became (029) 2087 2087. Perfectly logical, releasing massive new capacity and also retaining a single area code with local dialling (albeit 8 digits instead of 6).

Unfortunately, huge sections of the population misinterpreted this as the 'code' changing from 01222 to 02920 and you routinely see people writing their number as (02920) 123456 etc. Problem with that being that it's ingrained in people's minds that 02920 = Cardiff and they then get confused by newer numbers that don't start (029) 20xx xxxx.

That means you end up with massive misidalling as people see an unfamiliar new number like 029 2111 2111 and then either dial it as (02920) 2111 2111 or "correct" it to 029 2011 2111 - both leading to a wrong number.

020 for London

No, it's not "0207 and 0208" for London and never has been.

The whole point of the year 2000 changes for London was to increase capacity and move the city back from two separate codes with 7-digit local numbers to a single area code of 020 and 8 digit numbers. Swapping 0171 for 0207 and 0181 for 0208 would have achieved nothing.

Prior to 2000 you had:

(0171) 200 0000 through to (0171) 998 9999 for inner London

and

(0181) 200 0000 through to (0181) 998 9999 for outer London

Total: 2x 7,990,000 = 15,980,000 numbers

From 2000 London has been able to use:

(020) 2000 0000 through to (020) 9989 9999

Total: 79,900,000 numbers

So far, only numbers beginning with 3, 7 or 8 are in use.

The small added bonus is that now London is back to a single area code, you can dial any regular (020) landline number from any other with just eight digits.