My friend Sean, like a lot of people in Ireland, tells a good story. He used to work for the National Roads Authority; they couldn't call it the Irish Roads Authority, he liked to joke, because the abbreviation "IRA" was already taken.
In 2010, Sean organised an event to celebrate the completion of a highway linking Dublin to Belfast, in Northern Ireland. You could now commute between the two capital cities, which had once seemed worlds apart, in under two hours. One of the grandees invited to celebrate on a stretch of road outside Newry was Mr Martin McGuinness, the former Irish Republican Army gunman who, like a number of former paramilitaries, had reinvented himself as a politician and helped engineer the Good Friday Agreement, which brought an end to the three-decade conflict known as the Troubles in 1998.