030 number ranges such as 0300 and 0303 Numbers, can only be used by charity, public sector and not-for-profit organisations. If you don't meet Ofcom's criteria, then you will have to use 0333, 0330, 034 or 037 Numbers.
Ofcom considers that the bodies eligible to use 030 numbers should meet at least one of two basic criteria:
Ofcom's website has a document which provides guidance on bodies eligible to use 030 telephone numbers. This document will be updated when necessary, to provide guidance on how individual bodies will be considered as eligible to use 030 numbers.
Ofcom's Guidance on bodies eligible to use 030 telephone numbers