regex for all UK telephone numbers

Question

I am trying to validate UK telephone numbers, which are in the format of:

01234 567890

01234567890

02012345678

020 1234 5678

I have the following regex, which works for all apart from the 020 1234 5678

^\s*\(?(020[7,8]{1}\)?[ ]?[1-9]{1}[0-9{2}[ ]?[0-9]{4})|(0[1-8]{1}[0-9]{3}\)?[ ]?[1-9]{1}[0-9]{2}[ ]?[0-9]{3})\s*$

Does anyone know why this is?

Answer 1

You are missing a closing square bracket

^\s*\(?(020[7,8]{1}\)?[ ]?[1-9]{1}[0-9{2}[ ]?[0-9]{4})|(0[1-8]{1}[0-9]{3}\)?[ ]?[1-9]{1}[0-9]{2}[ ]?[0-9]{3})\s*$
                                      ^
                                     here

This should be working

^\s*\(?(020[7,8]{1}\)?[ ]?[1-9]{1}[0-9]{2}[ ]?[0-9]{4})|(0[1-8]{1}[0-9]{3}\)?[ ]?[1-9]{1}[0-9]{2}[ ]?[0-9]{3})\s*$

Further you can remove some stuff from your expression.

{1} is not need every character is still matched once

[ ] is also not needed, just replace it with a space

[8,9] is wrong. it will match 8, 9 and, . Use [89] is correct.

Then it would look like that

^\s*\(?(020[78]\)? ?[1-9][0-9]{2} ?[0-9]{4})|(0[1-8][0-9]{3}\)? ?[1-9][0-9]{2} ?[0-9]{3})\s*$

If you want to allow this not matched pattern 020 1234 5678 you could do for example

^\s*\(?(020[78]?\)? ?[1-9][0-9]{2,3} ?[0-9]{4})$|^(0[1-8][0-9]{3}\)? ?[1-9][0-9]{2} ?[0-9]{3})\s*$
               ^                 ^^
made the [78] optional        allows no 2 or 3 of `[0-9]`

See it here on Regexr

I have no clue if this is a valid UK phone number!

I fixed here also another bug in the regex a missing $ before and a missing ^ after the pipe |

Answer 2

If you can use Perl Number::Phone::UK can check if a number is valid, allocated, mobile, personal or business... and so on.

Answer 3

020 Does not follow with a 7 or 8.

The London phone code was unified into one single area code. 020 . The remaining numbers are the landline, as such the format 020 7123 4567 is correct. See ofcom website.

Answer 4

My JS solution

var total = 0;
var passed = 0;
var failed = 0;

var r = /^(?:(?:\(?(?:0(?:0|11)\)?[\s-]?\(?|\+)44\)?[\s-]?(?:\(?0\)?[\s-]?)?)|(?:\(?0))(?:(?:\d{5}\)?[\s-]?\d{4,5})|(?:\d{4}\)?[\s-]?(?:\d{5}|\d{3}[\s-]?\d{3}))|(?:\d{3}\)?[\s-]?\d{3}[\s-]?\d{3,4})|(?:\d{2}\)?[\s-]?\d{4}[\s-]?\d{4}))(?:[\s-]?(?:x|ext\.?|\#)\d{3,4})?$/;

var pass = [
    '(0123) 456 7890',
    '012 3456 7890',
    '+44 12345 67890',
    '+44 1234567890',
    '0044 1234 567 890',
    '0044 1234 567890',
];

pass.each ( function (value) {
    var result = r.test( value );
    console.log( value, (result == true ? 'ok' : 'failed') );

    total ++;
    if ( result == true ) {
        passed ++;
    } else {
        failed ++;
    }

} );


var fail = [
    '(0123) 456 78',
    '012 3456 789',
    '+44 12345 678',
    '0044 1234 567 89',
];

fail.each ( function (value) {
    var result = r.test( value );
    console.log( value,  (result == false ? 'ok' : 'failed') );

    total ++;
    if ( result == false ) {
        passed ++;
    } else {
        failed ++;
    }
} );

setTimeout(function () {
    console.log( "PASSED " + passed + ' / ' + total );
}, 500);