No, London has an area code of 020 for standard landline telephones.
However, +44 7xxx xxxxxx would be a United Kingdom mobile phone or personal number shown in international format. (07xxx xxxxxx domestically).
In the UK, mobile phones are not linked to geographic area codes - they are grouped together in the +44-7 (or '07' within UK) range regardless of location.
The telephone country code for the UK (including England) is +44. An international telephone number beginning with +44 7 is either a UK personal "follow-me" number (+44 70) or a mobile phone (+44 74 through +44 79). In either case, the person on the other end of the line could be literally anywhere in the world.
In North America, area code 447 (international: +1 447) has been assigned, but not yet implemented, as an overlay of area code 217 in central Illinois, including Champaign and Springfield. The overlay is expected to take effect in 2013 or 2014.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
A UK telephone number beginning with 079 (or +44 79 in international format) is a mobile phone.
This isn't a London code. It is the area code for Brentwood in Essex which is about 30 miles northeast of London.
The country code and area code of Slavutych, Ukraine is 380, (8~0)4479.
In the UK, area code 020 is London, but there are no numbers beginning with 020 2. Other countries may have similar telephone area codes.
London's telephone code is 020 followed by an eight digit number which will start with 3,7 or 8. The number that you have asked about is not a London number as you have described it.
The London phone directory no longer lists London telephone areas. All that can be gleaned from the given number is that 020 means that it is a London number and 8578 is somewhere in the outer London area.
UK telephone area code 020 is London and surrounding areas. It is not possible to narrow down the location any further with the information given. Furthermore, with number portability, any specific 020 number could be located anywhere in the greater London 020 area.
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.
In the UK, telephone area code 020 is London. A number beginning with 020 3432 is a "virtual" number that could be anywhere in London. Furthermore, with number portability any specific 020 number could be located anywhere in the London area, served by any local phone company.
UK area code 020 is London, but there are no valid numbers beginning with 020 4, much less 020 43. Also, the area code for London is just 020, not 020x or 020xx. There are no other UK telephone area codes beginning with 020.
There is no telephone area code 185 in Russia.
There is no area code 0208 in the UK. The area code for London is just 020, with 8-digit local numbers. A number beginning with 020 8749 is most likely a BT landline in Shepherds Bush, but with number portability any specific 020 number could be located anywhere in London, served by any local phone company.
UK telephone area code 020 is greater London. A number beginning with 020 8262 could be located anywhere in the greater London 020 area; that prefix is not associated with any particular borough, district, or neighbourhood. Furthermore, with number portability, any 020 number could be located anywhere in greater London, served by any local telephone company.