Use the country code for the United Kingdom, which is 44
From Los Angeles, this means dialling:
For example, the London number (020) 7946 0018 would be dialled from the USA as: 011 44 20 7946 0018.
Where only the eight-digit local London number is known, this should be prefixed with the London area code, [0]20. The number London 79460018 would become: 011 44 20 7946 0018.
In the UK, area code 020 is London. There is no area code 0208.
01274
This isn't a London code. It is the area code for Brentwood in Essex which is about 30 miles northeast of London.
020 is the telephone dialling code for all of London.
In the US, the 734-512 prefix is in Trenton, Michigan.
That address in Los Angeles is in telephone area code 323. The postal ZIP Code is 90047.
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.
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.
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.
UK telephone area code 020 is London, including both the former "Inner London" and "Outer London" zones. A number beginning with 020 7485 is most likely a BT landline in Kentish Town, but with number portability any particular 020 number could be located anywhere in the greater London 020 zone, served by any local telephone company.
Los Angeles has several telephone area codes, including 213, 310, 323, 424, 661, 747, and 818, plus several more in the immediate suburbs. The airport code for Los Angeles International Airport is LAX.
Area code 213 serves the central part of downtown Los Angeles, California. ZIP Code boundaries do not correspond to area code boundaries. To get a telephone number with a 213 number, you can get landline service at an address in central downtown Los Angeles, or you can request a 213 number from a mobile phone company or VoIP company (magicJack, etc.).