I don't know if the audio for this works outside the UK: https://www.bbc.co.uk/programmes/m002h38n
McDonald's Corporation v Steel & Morris [1997] EWHC 366 (QB), known as "the McLibel case", was an English lawsuit for libel filed by McDonald's Corporation against environmental activists Helen Steel and David Morris (often referred to as "The McLibel Two" ) over a factsheet critical of the company. Each of two hearings in English courts found some of the leaflet's contested claims to be libellous and others to be true.
The original case lasted nearly ten years which, according to the BBC and The Guardian, made it the longest-running trial in English history. McDonald's announced it did not plan to collect the £40,000 it was awarded by the courts. Following the decision, the European Court of Human Rights (ECHR) ruled in Steel & Morris v United Kingdom that the pair had been denied a fair trial, in breach of Article 6 of the European Convention on Human Rights (right to a fair trial), and their conduct should have been protected by Article 10 of the Convention, which protects the right to freedom of expression. The court awarded a judgment of £57,000 against the UK government. McDonald's itself was not involved in, or a party to, this action, as applications to the ECHR are independent cases filed against the relevant state.
Franny Armstrong and Ken Loach made a documentary film, McLibel, about the case.
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Chapter 5 of Paul Lewis and Rob Evans' 2012 book Undercover: The True Story of Britain's Secret Police is titled "McSpies". In recounting the history of the Special Demonstration Squad (SDS) it recounts the involvement of
undercover policemen Bob Lambert and John Dines in the activities which led up to the trial. The Guardian later reported that
Lambert had co-written the leaflet that was central to the libel trial. Steel has stated that Dines became treasurer of London Greenpeace.
Documents from the case showed that McDonald's private investigators had been receiving information from the Metropolitan Police. The Metropolitan Police were sued over this, which was settled out of court and with an apology and the Metropolitan Police undertaking not to share information from police computers with corporations.
https://en.wikipedia.org/wiki/McLibel_case