(0)

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Zero. Zip. Zilch. Nada. Nil. Nothing. Nowt. It's funny how a humble misplaced (0) can cause millions of people to misdial their international telephone calls every single day.


UK telephone numbers can be written in one of several ways:

National Format

All of the above follow the correct E.123 national format.

There are several different ways these numbers can be dialled, depending on where the caller is located:

  • When calling from another British landline or from any mobile telephone (whether British or foreign) and calling from within the UK, simply dial all of the digits to complete the call.
  • When calling from abroad, replace the initial 0 with +44. From any mobile telephone (whether British or foreign) the + can dialled as the literal + sign. From a foreign landline the + sign should be replaced by the international access code of the country that the call orginates from (00 in most of Europe, 011 from the US and Canada, 010 from Japan, etc). Follow that with the 44 country code and the rest of the digits (without the leading zero).

International Format

All of the above follow the correct E.123 international format.

There are several different ways these numbers can be dialled, depending on where the caller is located:

  • When calling from a British landline or from any mobile telephone (from a British or foreign mobile telephone alike) which is located within the UK, replace the +44 with a 0 and dial it and all of the remaining digits.
  • When calling from a British or foreign mobile telephone (either from abroad or from the UK), dial the literal + sign and all of the digits after it.
  • From a foreign landine or from any mobile telephone (whether British or foreign) calling from outside the UK, replace the + sign with the international access code of the country that the call orginates from (00 in most of Europe, 011 from the US/Canada, 010 from Japan, etc) then dial all of the remaining digits.


Writing telephone numbers in a non-standard way can lead to confusion and mis-dialling:

Non-valid format (UK)

  • +44 (0)161 645 2244
  • +44 (0)7810 482456
  • +44 (0)845 810 3355

The misguided intention is that this format signifies the (0) is dialled from within the UK but is dropped when calling from abroad.

Unfortunately that is the exact opposite of the description in the ITU-T E.123 standard for what the parentheses signify. A foreign caller following the definition in the ITU-T standard (in national format, dial parenthesised digits when calling from outside the area and optionally omit them when calling from within the area; do not use parentheses in the international format) will end up dialling +44 0161 645 2244, +44 07810 482456 or +44 0845 810 3355 and that will always result in a failed call. The (0) should not be included in the international format.

Non-valid format (Ireland)

  • +353 (1) 234 5678

Here, the area code is enclosed in parentheses, against the better advice of the ITU-T standard.

When faced with the above Irish telephone number, a person following the non-standard meaning (drop digits in parentheses when calling from abroad), will find that dropping the (1) leads to a failed call as a vital digit (the area code) is missing from what has been dialled. Parentheses should not be used at all in the international format. The correct international format is +353 1 234 5678.

Non-valid format (Italy)

  • +39 (0)6 345 6789

When faced with the above non-standard format Italian telephone number, dropping the (0) leads to a failed call as a vital digit is missing from what has been dialled. The leading 0 of an Italian telephone number IS dialled from abroad. Parentheses should not be used at all in the international format. The correct international format is +39 06 345 6789.


The international format should include all of the digits that must be dialled from abroad, and only the digits that must be dialled from abroad. The international format should not include any parentheses.

External links

See also