‘Rouse tempers, goad and lacerate, raise whirlwinds.’ Those were the words that Kenneth Tynan, the most celebrated drama critic of the 20th century, had pinned above his desk. During my five-year stint as The Spectator’s theatre critic I did my best to follow that philosophy. But according to a new set of guidelines devised by Equity and embraced by the National Union of Journalists, reviews should be ‘balanced, fair and designed to be productive’.