I WAS TREMBLING. Not because I was about to do something risky or scary – quite the opposite. This was a situation I had been in many times before, but I was nervous about what was going to happen next.

I was on the Concert Hall stage at the Sydney Opera House looking at an audience of about 2,000 people. Not to perform music, thankfully: I’d been invited to speak about why Australia should abolish its private schools. Typical symptoms of performance anxiety include dry mouth, sweaty hands, trembling knees and racing heartbeat – I experienced all these and more. Even my vision had changed thanks to the bright spotlights turned towards me.