is possible to override the carrier pre-selection (CPS) on a per-call basis, dialling a special code before the number, e.g. 1280 for BT, 1664 for LowerCall, or 1844 for Daisy. Ofcom defines the range for these as: "124 to 140, 143 to 146, 148 to 149, 160 to 169, and 181 to 189 inclusive. Numbers of up to 5-digits used to access an Indirect Access Provider (‘Type B Access Codes’)". History Telephone numbers in Overseas Territories Telephone numbers in British Overseas Territories do not come under the UK telephone numbering plan. These calls are treated as international calls. Below are the access codes for the overseas territories: North American Numbering Plan Anguilla +1 (264) xxx xxxx Bermuda +1 (441) xxx xxxx British Virgin Islands +1 (284) xxx xxxx Cayman Islands +1 (345) xxx xxxx Montserrat +1 (664) xxx xxxx Turks and Caicos Islands +1 (649) xxx xxxx Others British Antarctic Territory +44 (Shared with the UK) British Indian Ocean Territory +246 Falkland Islands and South Georgia and the South Sandwich Islands +500 Gibraltar +350 Saint Helena and Tristan da Cunha +290 Ascension Island +247 Akrotiri and Dhekelia +357 (Shared with Cyprus) Pitcairn Islands +64 (Shared with New Zealand) See also Big Number Change List of dialling codes in the United Kingdom List of UK dialling codes covering Wales Non-geographic telephone numbers in the United Kingdom Telecommunications in the United Kingdom Telephone number Telephone number portability Telephone numbering plan Telephone numbers in Ireland UK telephone code misconceptions—includes the common "0207" and "0208" misconceptions Calling party pays Notes References External links UK Numbering Policy section of Ofcom's website UK National Telephone Numbering Plan (PDF) Ofcom – Telephone Area Code Tool – UK dialling code lookup Ralph Adam, 'Send a boy – or dial it yourself? numbering for the information society', ASLIB Proceedings, 51:1, January 1999 UK telephone numbering plan in detail Regular Expressions for Validating and Formatting GB Telephone Numbers The first 25 years of STD code changes summarised (PDF) UK Area Codes lookup United Kingdom Telephone numbers