ðə ɡɹˈeɪɾɚ lˈʌndən bˈaʊndɚɹi vˈɛɹiz fɹʌm tə fɹʌmðə sˈɛntɚ ænd kˈɑːnsɪkwəntli sˌʌm ˈaʊɾɚ dˈɪstɹɪkts ɑːɹ kˈʌvɚd baɪ ɐdʒˈeɪsənt kˈoʊdz ænd ɪn sˌʌm plˈeɪsᵻz ðə zˈiəɹoʊ twˈɛnti kˈoʊd ɛkstˈɛndz bᵻjˌɔnd ðə ɡɹˈeɪɾɚ lˈʌndən bˈaʊndɚɹi.
The Greater London boundary varies from  to  from the centre and consequently some outer districts are covered by adjacent codes and in some places the 020 code extends beyond the Greater London boundary.