Where is UK telephone number 02030?

invalid code

First of all, telephone country codes never begin with zero.

If we take that number as +20 30, that would be country code +20 (Egypt), but the next two digits pose a problem. Egyptian area code 03 (which is to say +20 3) is Alexandria, but local numbers cannot begin with zero.

Conclusion: invalid international code

There are many countries that have domestic numbers beginning with 02030. For example, in the UK, 020 is London. In the Netherlands, 020 is Amsterdam.