evidence: The UK-Ireland border, which is proving to be the one puzzle Brexiteers can’t solve, runs through the back garden of his family home. [...] "I grew up at the border, I know how porous it is and it just won’t work if you try to control it here," says O’Reilly, furious that with a year to go until Brexit no practical solution has been agreed. [...] The Irish Government has estimated around 30,000 people cross the border every day. Most are commuting to work, travelling to see friends and family or to use health services. Thousands of them are schoolchildren.