This is the main data output of the UKRR project. The data was extracted using the LARCH database on 29th March 2019. It includes everything submitted by all libraries during Phases 2 and 3, but only some data from Phase 1. Phase 1 did not use the LARCH system, and some of the Phase 1 submissions were retrospectively added, but others were not. As far as records show, of the Phase 1 contributors, this dataset includes: All the Phase 1 contributions from Liverpool, Newcastle and St Andrews. Some of the Phase 1 contributions from Birmingham and Southampton. None of the data from Cardiff, Exeter and Imperial. The dataset includes information on journal title changes and cataloguing inconsistencies (all of which are listed in column B), grouping them together and assigning a BL Overlap number (column A), and giving all relevant International Standard Serial Numbers (ISSNs) in Column C. Column D is the number of different titles under which a specific journal was offered. Column E shows the number of times material from that journal was offered. Column F shows the libraries that offered the material, as well as the number of times each library offered it. All UKRR participant libraries agreed to release the data without anonymisation in the interests of openness and to allow greater scope for future analysis.