Warmth and wisecracks on Cameron's White House visit David and Samantha Cameron have been given a warm welcome at the White House as the UK and the US celebrate their "special relationship." Barack and Michelle Obama led the reception, marked by some presidential humour over historically troubled times between the allies. The White House was, after all, once set alight by British troops! "It's now been 200 years since the British came here to the White House under somewhat different circumstances," President Obama joked, triggering laughter among the VIPs gathered on the lawn. They made quite an impression. They really lit up the place! But we've moved on. And today, like so many presidents and prime ministers before us, we meet to reaffirm one of the greatest alliances the world has ever known," he told a joint,outdoors press conference. Pomp and ceremony were aplenty before the pair got down to the serious business of talks focussed on Syria, Afghanistan and Iran's nuclear programme. After the meeting, Obama said that he and British Prime Minister Cameron agreed there was still time to pursue a diplomatic solution with Tehran, while keeping up the pressure. More about: Barack Obama, David Cameron, United Kingdom, USA