You asked
Please provide a list of "all currently used surnames (last names/family names) and their usage frequency" in the British Isles.
We said
Thank you for your request for a list of all currently used surnames (last names/family names) and their usage frequency in the British Isles.
Unfortunately, we have not undertaken analysis on the names collected on the 2011 Census forms, so we do not hold census datasets that meet your requirements. Furthermore, we have no plans to produce and release this type of analysis.
Data (with names) from censuses before 1921 may be available from The National Archives https://www.nationalarchives.gov.uk/.
You can contact the ONS Census Customer Services directly with any England and Wales census-related questions you may have in the future. For more information visit: https://www.ons.gov.uk/census/censuscustomerservices or email us at: census.customerservices@ons.gov.uk
If you would like to keep up with developments on the 2021 Census programme (or any other areas of ONS) please register for email updates at the following address:
https://public.govdelivery.com/accounts/UKONS/subscribers/new