Ofcom have announced changes to the General Conditions and supporting guidance to improve the accuracy of the CLI data. Rules will be modified to require providers to identify and block calls with CLI data that is invalid, does not uniquely identify the caller, or does not contain a number that is dialable.
Furthermore, guidance will be changed to require providers to:
• clarify that the format of a CLI should be a 10- or 11-digit number
• make use of information that identifies numbers which should not be used as CLI
• identify calls originating abroad that do not have valid CLI and block them
• identify and block calls from abroad spoofing UK CLI
• prohibit the use of 09 non-geographic numbers as CLI

These changes will come into force on 15th May 2023.
CCUK responded to the original call for evidence, and we will provide guidance, advice, and support to members who need it.