IT sometimes seems that Brexit will never end. Next week marks the fifth anniversary of Britain’s formal withdrawal from the European Union. A few days later Sir Keir Starmer will attend his first informal summit of EU leaders. A formal EU-UK summit will follow in April to kick off talks on a “reset” in relations. Sir Keir wants to build on the needlessly thin trade deal agreed by Boris Johnson, a former prime minister. Most EU leaders favour closer links with an important neighbour.