I am typing up my itinerary with contact information for family and officemates, and am stumped by the variety of telephone combinations I see. There appears to be a three- or four-digit prefix, depending on whether there is a 0 in front or not. Sometimes the prefix is 5 digits and the number following the hyphen is 6 digits; where the prefix is 3 or 4 digits (again depending on the 0), the number after the hyphen is 7 digits.

Obviously the hyphen is irrelevant for dialing purposes, but the prefatory 0 is confusing.

What is the rhyme or reason? Thanks

When calling from outside of UK, drop the 0. From US you would dial 011+country code+plus all the numbers, EXCEPT the zero.

a quick (and probably slightly inaccurate in places!) explanation of the prefixes:

london phone numbers are all start 020. that's the prefix for london. in central london the next number is always a 7, while in outer london the next number is always an 8. there are then 7 digits after that.

other big cities have 4 digit prefixes, for example, glasgow is 0141. this is followed by 7 digits.

smaller towns and cities have 5 digit prefixes, for example cambridge is 01223. this is then followed by 6 digits.

and finally, very small places in the country (i only know one person with a phone number like this) can have 6 digit prefixes followed by 5 digits.

all phone numbers in the UK do start with a 0 - i imagine where you've seen them without the 0 it's because they've been written for someone outside of the UK, where, as the other poster said, you drop the 0.

did that make sense?

There are always 10 digits after the 0. There are no numbers that don't begin with a zero.

Inside Britain, you don't need to dial all ten if you are phoning within a specific area. So if, after the 0, there's a four digit area code and you're in that area, you need dial only the last 6. To the best of my knowledge there are now ONLY three or four digit area codes.

HOWEVER, there's no disadavantage (except a second or two wasted) to your dialling all 11 (10 plus that zero) every time. If it's a local call, you'll be charged for a local call, even though you've dialled a long distance prefix. So you don't need to work out which is the area code and which is the local number.

unless it's changed within the last month, there is at least one area code with a 0 followed by 5 digits. honest. it's in the back of beyond in the lake district, but it exists

There are also numbers that are non-geographic (ie. they don't local area codes begining with 01 or 02).

numbers beginning with 07 are for mobile phones and pagers
numbers begining 08 are either free or up to the local or national rate (generally 080, 084 and 087 respectively). You often see these for central reservations for hotels for example.
Numbers beginning 09 are generally premium rate numbers, which can have varying charges.
With any of these numbers the position of the prefix/number break doesn't matter, as you always dial the whole number.

There are probably also some numbers that don't fit this pattern at all for no particular reason.

Thanks, VickiH - by coincidence, one of our destinations is the Lakes, and one of the numbers is a 6 digit prefix/5 digit number (015394-xxxxx).