The Guardian obituary of Brian White, the Belfast man who served honourably but briefly as a Labour MP, included a reminder that there was a time – not too long ago – when the border between Northern Ireland and the rest of the United Kingdom resembled, at times, the type of border that people have been suggesting, post-Brexit, might exist between Northern Ireland and the Republic. In 1974, during the earliest phase of the so-called Troubles, when the Prevention of Terrorism Act was used as a control on travel between these two parts of the UK, the 17-year-old White was asked for his passport at Heathrow on arriving from Belfast. ‘This isn’t the Soviet Union,’ he said, ‘we don’t have gulags here.’ Another traveller whose sensibilities were similarly exercised during this period was Seamus Heaney,