What happened
Leveson Part 1 (2011–12) examined the culture and ethics of the press while criminal trials were pending; Part 2 was explicitly deferred, not abandoned, so that it could later investigate what corporate managements knew, how far unlawful conduct extended, and why the original police investigations failed. Cameron told victims in 2012, in Parliament, that the second stage would happen.
What the cancellation left uninvestigated was later established piecemeal, at private expense, in the civil courts: the 2023 Fancourt judgment found Mirror Group's unlawful information gathering was concealed from the board, Parliament, and the Leveson Inquiry itself; NGN's 2025 settlement with Prince Harry admitted for the first time that unlawful activity had occurred at The Sun. Both were exactly the corporate-knowledge questions Part 2 existed to answer, and both took a claimant with royal resources to extract — a mechanism unavailable to the ordinary victims to whom the inquiry had been promised.
The government's stated rationale was that the media landscape had changed and the inquiry was no longer proportionate. Its practical effect was that no state process ever examined the cover-up, and the Section 40 costs-shifting provision that would have given ordinary claimants access to justice against newspapers was never commenced and was finally repealed by the Media Act 2024.
Evidentiary class: government decision of public record (2018 statement and Commons vote), with Leveson's own published objection.