“HMRC uses the online form CT600 to collect and store corporation tax return information and computations online. For the last available financial year, I require a spreadsheet/csv file of CT600 corporation tax filings for all of the following UK registered corporations: • Limited Companies • Unincorporated Associations • Charities and Community Amateur Sports Clubs (CASCs) • Non-Profit Organisations Community Interest Groups (CICs) NOTE: 1. No data columns are to be filled in the CT600 cohort that could identify corporations or individuals. (These include company name, company number, tax reference, contact details or banking information). 2. The company name should be replaced by a sequentialnumber, and any identifiable information replaced by a dash. All other non-identifiable information filed on the CT600 form by the individual company should be disclosed under that sequential number”
“On29 November 2024 , I made a request to HM Revenue and Customs (HMRC) under theFreedom of Information Act 2000 (FOIA) for anonymised corporation tax return data (CT600). My request explicitly required that all direct identifiers be removed and that any other data fields which pose a risk of re-identification be excluded, in accordance with the Information Commissioner's own Anonymisation Code of Practice. HMRC refused the request undersection 44(1)(a) FOIA , citingsection 23 of the Commissioners for Revenue and Customs Act 2005 (CRCA). The Information Commissioner upheld HMRC's reliance on this prohibition. I contend that this decision is legally flawed for the reasons set out in my attached Skeleton Argument and supporting documentation.”
“It is not necessary for HMRC to demonstrate that an information requester or any other person would be in a position to identify a person to whom requested information relates in order to withhold that information in reliance on section 23 of the CRCA. It is merely necessary to show that a person (a legal entity) would be in a position to identify the person to whom the requested information relates. This would also include self-identification.” e. The risk of deduction arises through mosaic effects, including from information already in the public domain, information which may foreseeably come to light (including through self-identification) and other information not in the public domain/ This risk is heightened and illustrated by—but does not arise exclusively from—the availability of modern tools to effect ‘jigsaw identification’ by drawing together these disparate pieces of information and making probabilistic deductions. It agrees with the IC that the requested information “is a rich source of highly sensitive financial data […] [e]ven where this information does not match exactly, the richness of the data available is likely to enable identification, particularly of high-profile organisations”. f. In relation to anonymisation, the format requested is a pseudonymised dataset, in which unique identifiers are “replaced by a sequential number”