I need a regular expression that only validates UK mobile numbers.

A UK mobile number can be between 10-14 digits and either starts with 07, or omits the 0 and starts with 447.

Importantly, if the user adds +44 it should be rejected.

So these would be valid:

07111111111

447111111111

and these would be invalid:

+4471111111111

021929182711

00701029182

What I have so far:

rule = re.compile(r'^\+?(44)?(0|7)\d{9,13}$')if not rule.search(value):msg = u"Invalid mobile number."raise ValidationError(msg)

This does not validate according to my rules yet; could someone help?

The following regex seems like it would fit your requirements, if I understand them correctly.

Not allowing a + sign is very easy as you're only creating a whitelist of values, and the plus isn't among them.

^(07[\d]{8,12}|447[\d]{7,11})$

As was mentioned in the comments for this answer, the square brackets are not necessary here. I included them to make my own reading of this regex a little easier on my eyes. However, the following works just as well:

^(07\d{8,12}|447\d{7,11})$