The UK area code for Portsmouth, England, is 023.
In 2000, Portsmouth changed from area code 01705 with 6-digit local numbers, to area code 023 with 8-digit local numbers. 01705 xxx xxx changed to 023 92xx xxxx. This change led some people to erroneously refer to the new code as 02392, but in fact the area code is 023.
At the same time, Southampton numbers changed from 01703 xxxxxx to 023 80xx xxxx.
In more recent times, Portsmouth has started using the 93xx xxxx number range and Southampton has started using the 81xx xxxx and 82xx xxxx number ranges.
It remains true that all Portsmouth local numbers begin with 9. Local numbers in area code 023 beginning with 8 are in Southampton. Although Portsmouth and Southampton share an area code, calls between them are not considered to be 'local'.
Calling internationally, both Portsmouth and Southampton are in area code +44 23, with 8-digit local numbers.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, and some other countries use different prefixes.)
01931 is the telephone code for Shap, Westmorland (near Penrith in Cumbria).
01691
UK telephone area code 0161 is Manchester, but 0161 553 is an invalid number block.
UK telephone area code 01954 (or +44 1954 in international format) is Madingley, Willingham, near Cambridge.
A UK telephone number beginning with +44 754 is a mobile.
Portsmouth's area is 15.5 square miles (40.3 square kilometers).
01792 is the area code for Swansea
Until the early 1990's, area code +44 21 (or 021 within the UK) was Birmingham, which is now area code +44 121 (or 0121 within the UK). There has never been an area code +44 217 (or 0217) in the UK.
In the UK, area code 020 is London, but there are no numbers beginning with 020 2. Other countries may have similar telephone area codes.
UK telephone area codes were first assigned in 1958.
00 + 1 + Area code + telephone number.
UK area code 0141 is Glasgow, which has post codes beginning with G.