A few weeks ago, Denis Cochrane, the choirmaster of a leading Roman Catholic school, was found guilty on seven counts of indecent assault against boys under 16. He was sought after as a music teacher (one of his pupils was Richard Branson's son) and had a reputation as an organist. Cochrane was also something of a world expert on the Titanic, giving lectures and exhibiting his huge collection of artefacts from the wreck. Denis Cochrane taught my son and assaulted him on numerous occasions. Over the last 19 months I have discovered that, however strong the evidence, it is nearly impossible to make an accusation of molesting children stick against such an influential and admired man.One evening, when my husband was away on a business trip, two police officers rang our front-door bell.