The thing I most regret having failed ever to ask brave, haunted, wise Sean O’Callaghan when I last saw him at a friend’s book launch was ‘So tell me about Shergar.’

It has long been known, of course, that the legendary racehorse — one of the five greatest in the last century, according to Lester Piggott who rode him to victory in the Irish Derby — was kidnapped in 1983 by the IRA and never seen thereafter.