From aa-asterisk.org.uk wiki
- See Sabc.txt for the UK area code list.
While the area code for London is "020", in fact the "020" consists of two distinct elements:
- The "20" part is the National Destination Code.
Dialling the trunk code signals that the following digits are a National Destination Code.
The trunk code is not needed when the number is dialled from abroad.
From abroad, dial the +44 country code followed by the NDC and local subscriber number.
There's also a replacement file for their sabc.txt data with the errors corrected and noted.
- National Telephone Numbering Plan
- Number format
- Charge group
- DE block
- 01 numbers
- 02 numbers
- ELNS areas
- Mixed areas
- Regular Expressions for Validating and Formatting GB Telephone Numbers
- Local dialling rules for GB telephone numbers
- Errors in Cisco UK Numbering Plan Documents
- UK Area Codes List at Wikipedia.org
- Codelook at TelecomTariffs.co.uk
- UK Area Codes List at AreaCodes.org
- UK Area Codes List at TelephoneNumbers.co.uk
- UK Area Codes List at NumberingPlans.com
- UK Area Codes List at Ofcom.org.uk
- UK Area Codes as they were in the 1990s
Very few other online lists are remotely close to being accurate or up-to-date.