Luke was brought up in Kildare but educated in England. His prep school was St Ronan's in Kent, which his uncle-in-law, Mark Shand, had coincidentally also attended over ten years earlier. 'It was like the school out of Decline and Fall,' Luke says. 'Totally shambolic. We'd be playing cricket and the headmaster would say, "If you hit a four now, I'll give the whole school a day's holiday tomorrow." It was so cosy and magical and odd.' He later followed in his father's footsteps by going to Eton, but left at 16 with one A level in drama and, after a genteel gap year studying history of art in Paris, Venice and London, got a job as an assistant stage manager at The Abbey Theatre, Ireland's National Theatre, in Dublin.