US ambassador to Nato has called for all allies who are ‘lagging behind’ to step up immediately Keir Starmer is likely to face a diplomatic row at his final major international summit this week after Washington’s ambassador to Nato called for alliance members who are “lagging behind” on defence spending to step up. The prime minister is due to arrive in Ankara on Tuesday for the annual Nato summit, where the UK commitment will be under scrutiny following the release of the government’s defence i