[she is] a wave breaking on a rock, because although she is sweet and pretty and charming, she also has a basic streak of toughness and tenacity. … when a wave breaks on a rock, it showers and sparkles with a brilliant play of foam and droplets in the sun, yet beneath is really hard, tough rock, fused, in her case, from strong principles, physical courage and a sense of duty. Sir Hugh Casson on Queen Elizabeth the Queen Mother.