Free Speech Tsar: Arif Ahmed on how to avoid the 'abyss' of political violence

How do you protect and police freedom of speech on campus and in society?

Arif Ahmed is a Cambridge Philosopher who is now responsible for enforcing new freedom of speech rules on universities, colleges and students.

He took office at a time when there is particular focus on a vexed question: where the boundary should lie between free speech - which should be protected - and speech that threatens, intimidates and leaves people feeling unsafe, which can and should be restricted.

He talks to Nick about why he ended up so passionate about...