Herbert Kretzmer, who has died aged 95, was at various times an influential theatre and television critic on Britain’s two rival mid-market newspapers, the Daily Mail and the Daily Express, before finding greater fame and infinitely greater fortune with the English libretto for the West End hit musical Les Misérables, widely reckoned the greatest show in musical history.With Alain Boublil (original French lyrics) and Claude-Michel Schönberg (music), Kretzmer was the third of the triumvirate who