Most of his teeth have been cracked because of “many” assaults and he has sustained brain and eye injuries as a result of “bashings by Mugabe’s thugs and neo-Nazis in Moscow”.

The harsh reality of life as a human rights activist was recently highlighted at Verulam School, Brampton Road, by Peter Tatchell.

Peter, director of human rights organisation, Peter Tatchell Foundation, gave a lecture to sixth form students as part of the school’s Engaging Minds series.

A spokesman for the school said: “Peter provided a fascinating insight into human rights violations that exist across the world and the range of experiences he has faced when challenging these issues.

“He also outlined the energy and commitment needed to spend 48 years fighting for what you believe in.”

Writing for The Guardian last year, Peter admitted decades of campaigning have taken their toll, particularly as he has endured hundreds of arrests and violent assaults. His dentist has reconstructed his cracked teeth.

Verulam School has also been visited by BBC arts editor Will Gompertz, whose life is far calmer than Peter’s.

He gave advice on interview success and championed, “the role of the arts and the centrality of the artist in helping us to see the world”.