Date | Code | Notes |
---|---|---|

Up to 1989 | 01 | Seven-digit local numbers. |

1989 to 1992 | 071 and 081 | London was split in two to double the amount of available numbers. |

1992 to 1999 | 0171 and 0181 | National codes were all changed to add a 1 after the initial 0. |

June 1999 to April 2000 | 020 with 7 or 8. | Introductory period - the previous dialling codes continued to work. Local numbers were still dialled as 7 digits, e.g. 123 4567\n |

2000 to present | 020 | Eight-digit local numbers. One code for all of London. |

Before 1989, there was one dialling code for London: 01, plain and simple. Admittedly getting particular numbers allocated was a pain, but it was due to overcrowding in the number range that the numbers were split into inner and outer London. *(See the page Locale Docklands for a reference to this.)*

From 1989, the dialling codes changed FOUR times:

\nDate | Code | Notes |
---|---|---|

Up to 1989 | 01 | Seven-digit local numbers. |

1989 to 1992 | 071 and 081 | London was split in two to double the amount of available numbers. |

1992 to 1999 | 0171 and 0181 | National codes were all changed to add a 1 after the initial 0. |

June 1999 to April 2000 | 020 with 7 or 8. | Introductory period - the previous dialling codes continued to work. Local numbers were still dialled as 7 digits, e.g. 123 4567\n |

2000 to present | 020 | Eight-digit local numbers. One code for all of London. |

In 1999, the exchange codes were properly reorganised to be 4 digits long, with the local number 8 digits long. It is no longer possible to determine the location of a subscriber within London based on the area code.

\nIt can be a good indicator of how long a firm has been in business if it has a sign using one of the older dialling code conventions (and also of how much they care about their frontage).

\nSome outer London boroughs are partly covered by other codes:

\n- \n
- 01322 [Dartford]:
**Bexley**(Crayford, Erith, Northumberland Heath, Slade Green, Barnes Cray, Belvedere) \n - 01689 [Orpington]:
**Bromley**(Orpington, Farnborough);**Croydon**(New Addington) \n - 01708 [Romford]:
**Havering**(Romford, Rainham, Hornchurch, Upminster, Harold Wood, Gidea Park) \n - 01895 [Uxbridge]:
**Hillingdon**(Ruislip, Uxbridge, Harefield, West Drayton, Cowley) \n - 01923 [Watford]:
**Hillingdon**(Northwood) \n - 01959 [Westerham]:
**Bromley**(Biggin Hill, Cudham) \n

All the following codes are considered local when dialled from 020 numbers:

\n- \n
- 01322 Dartford \n
- 01372 Esher \n
- 01689 Orpington \n
- 01707 Potters Bar \n
- 01708 Romford \n
- 01727 St Albans \n
- 01737 Redhill \n
- 01753 Slough \n
- 01784 Staines \n
- 01883 Caterham \n
- 01895 Uxbridge \n
- 01923 Watford \n
- 01932 Weybridge \n
- 01959 Westerham \n
- 01992 Hoddesdon \n