They gave away thousands to pet causes such as the Glastonbury pop festival and Release.

"They have a philosophy," Harker told me at the time. "They believe industrial society will collapse when the oil runs out and that the answer is to change people's mindsets using acid. They believe LSD can help people to see that a return to a natural society based on self-sufficiency is the only way to save themselves.

"Dick Kemp told me he met Francis Crick at Cambridge. Crick had told him that some Cambridge academics used LSD in tiny amounts as a thinking tool, to liberate them from preconceptions and let their genius wander freely to new ideas. Crick told him he had perceived the double-helix shape while on LSD.