UK telephone code misconceptions
As a consequence of these changes, many people were left with a misunderstanding of how the system of area codes and local numbers operates.
[4] Owing to number-capacity constraints, fixed line callers in Bournemouth, Poole and Christchurch (01202) must dial the full STD code even when calling local numbers.
[5] From October 2014, similar schemes were implemented in Aberdeen (01224), Bradford (01274), Brighton (01273), Middlesbrough (01642) and Milton Keynes (01908).
[6] Some telephone service providers differentiate ordinary calling costs using the relevant area code(s).
Until STD was introduced, only telephone operators could connect calls over the trunks (long-distance links between major exchanges).
The leading 0 is not part of an area code,[citation needed] which is why international callers dialling into the UK must not dial it.
Relatively few subscribers could dial trunk calls, so the 01 code was not generally included as part of the published telephone number.
This restriction was eventually phased out as exchanges were modernised and the STD code was shown in brackets to standardise with the format used in non-AFN areas, e.g. Canterbury (0227) 234567.
To free up more numbers across the UK for future use, on Easter Sunday, 16 April 1995 (dubbed "PhONEday"), an extra digit "1" was inserted after the initial zero into all except five geographical area codes nationwide, so inner and outer London became 0171 and 0181 respectively: for example, (0171) 222 1234.
[10][11] Possible causes for the misunderstanding include the confusion created during the period from 1 June 1999 to 22 April 2000, where it was not possible to dial eight-digit local numbers; the fact that people had become very much accustomed to the audio rhythm of a four-digit area code (from hearing the old codes, "0171" and "0181" repeated previously); and that incorrectly formatted caller ID data continues to be transmitted on some telephone networks even as of 2012.
Numerous examples of incorrectly formatted telephone numbers may still be seen in and around London, including signwriting on shop-fronts and commercial vehicles, and in newspaper advertisements.
Confusion is also caused by exchange automated changed number announcements where the voice synthesiser assumes that all area codes have four digits and places the spoken pause incorrectly.
Owing to the lingering confusion, people unaware of the correct format are beginning to assume erroneously that there is now a new London code, "0203".
[16] Although the problem is most prevalent in London, similar misconceptions also affect other area codes which were created as a result of PhONEday and the Big Number Change.
ITU-T Recommendation E.123 states that parentheses should not be used in the international notation,[22]: 3 the correct format being +44 20 7946 0234; the in-country form would be 020 7946 0234, shown separately.
