It takes a conflict to really show the cost of something. Teachers’ strikes at private schools are revealing the true cost – or value – of public sector pensions.

Surprisingly, private and state school teachers in Britain shared the same retirement provision, at least until recently. When they signed employment contracts, both received membership of the Teachers Pension Scheme, a government-run defined benefit fund paying a generous inflation-proof pension linked to average salary. But now, private schools are leaving the TPS in droves, provoking an unprecedented reaction from their staff, in the form of teacher strikes.