There is no STD code '0207' in England.
However, 020 is the area code for London, always followed by an eight-digit local number; the "7" following "020" is in fact part of the eight-digit 'local' number.
Occasionally people still display numbers with the spaces in the wrong place, making it look as though the code is 0207, 0208, 0203, etc...
More specifically, most (but not all) UK phone numbers beginning (020) 7xxx xxxx are likely to be in Central London. http://www.magsys.co.uk/telecom/codelook.asp features a tool that may help you confirm a more specific location.
Note that there is no longer any official distinction between inner and outer London in phone numbers - it's quite possible for an (020) 7 number to be used in the outer suburbs, or for (020) 8 numbers to be used in Central London.
In the UK, there is no area code 0207. Area code 020 is London. Number portability means that it is no longer reliably possible to narrow down a London number to a particular neighbourhood by the first few digits of the number. In fact, the "inner/outer" distinction formerly in the digit 7 or 8 following the area code, no longer holds firm.
020 is London. 020-3 numbers can be anywhere in London. The operator who "owns" this number is Frontier Systems. Note that the area code for London is just 020, not 0203 or 0207 or 0208.
If this is a UK telephone number then the (020) area code represents LONDON. London numbers have eight digits and begin 3xxx xxxx or 7xxx xxxx or 8xxx xxxx. The other unused numbers are for future expansion. There is no such area code as 0207 or 0208. The writer has not formatted the number in the correct way. The correct format is always: (020) xxxx xxxx or: +44 20 xxxx xxxx
All UK area codes begin with a 0. There is no area code 6010 in the UK, and there is no 06010 code either.
UK area code 020 is London.
There is no 01134 code in the UK.
There is no area code 20 in the UK
UK domestic area code 020 is London. Although you will often see references to area codes 0208, 0207, and 0203, these are incorrect; the correct area code is just 020, and the next digit is the first digit of the 8-digit local number. However, there are currently no valid numbers beginning with 020 8103.
The country code and area code of Aberdeen, United Kingdom is 44, (0)1224.
In the UK, 0121 is the area code for Birmingham.
Cambridge is in area code 01223, or +44 1223 from outside the UK.
Until the early 1990's, area code +44 21 (or 021 within the UK) was Birmingham, which is now area code +44 121 (or 0121 within the UK). There has never been an area code +44 217 (or 0217) in the UK.