Just over 125 years since its initial record-breaking run, The Mikado remains Gilbert and Sullivan’s most popular operetta. For a staggering fifth of that total time, it has also been virtually synonymous with Jonathan Miller’s dazzlingly inventive and stunningly stylish song-and-dance staging, which has proved an unfailing ‘source of innocent merriment’ ever since it first graced the London Coliseum stage in 1986.