21/06/2013 11:34 BST | Updated 21/08/2013 06:12 BST

McLibel Leaflet 'Co-Written By Undercover Police Officer Bob Lambert'

The McLibel 2, Helen Steel and David Morris outside McDonald's in the Strand, after winning their case in the European Court of Human Rights in Strasbourg.

An undercover police officer posing for years as an environmental activist co-wrote a libellous leaflet that was highly critical of McDonald's, and which led to the longest civil trial in English history, costing the fast-food giant millions of pounds in fees.