Area code creating apple ID

I'm trying to create a new apple ID. I live in the Netherlands but have a UK number. Every time I try to type in my number (with United Kingdom selected), it tells me "please choose an area code which matches the name of the country". My mobile phone doesn't have an area code. What do I type in this box? I've tried the first 2-3 digits of my phone number with and without +44 or 0044.

Solution 1:

UK numbers are all 11 digits, or country code plus 10 digits, omitting the leading zero.

so either
01234 567 890
or
+44 1234 567 890
[spaces only for legibility].

UK mobiles all start with 07 [or +44 7] - so the 'area code' is 07 nnn or +44 7 nnn

Just for extra information, adding your own country code to all domestic numbers does not affect call cost whilst in that territory, these days the systems are smart enough to figure it out.

00 international designations are only for dialling from landlines which can't use the + symbol.

Solution 2:

Had me scratching my head wondering what I was doing wrong until I saw the last comment on this post. Thanks @TMG

I've put the first 3 digits of my phone number as area code and it worked. However the form validation is really crappy there: The area code field turned red with no explicit validation error displayed, yet I was still able to click Continue and it proceeded just fine.