Accompanied by his wife Marie-France van Heel, Burnham earlier met King Charles III at Buckingham Palace to become the head of government after Keir Starmer resigned.Burnham, 56, arrived at Downing Street to resounding applause from supporters and acknowledged he was the country's seventh prime minister since the start of 2016.Britain needed to show the world it could "regain stability", he said, vowing to offer "a new political model" and "build a new economy".In foreign policy goals, he told broadcasters earlier his first calls would be to US President Donald Trump and Ukrainian leader Volodymyr Zelensky, to whom he will offer reassurance that "I will be with him 100 percent".In his brief speech outside Downing Street, the new Labour leader said he would "bring forward a new plan for Britain, a 10-year plan", without giving specifics.Naming short-term goals, he promised to "give people some breathing space now, some help with the cost of living."He also said his first instruction would be a pledge to "end rough sleeping", a measure he attempted to implement as a regional mayor in northern England, although it was not fully successful.Other announcements included a pledge to reindustrialise Britain through public procurement and to build more public housing.'Stronger, fairer'Starmer departed Downing Street earlier, insisting his short time in office had made Britain a better place."I am confident that Britain is now stronger and fairer than it was two years ago," Starmer told reporters in his farewell speech outside Downing Street."I go with good grace, I go with a smile, and I go proud of everything that we have achieved," he added.Burnham will face an in-tray overflowing with challenges with little time to make his mark with a nationwide election due in 2029.In an interview with The Times published late Sunday, Burnham said he wanted to draw a line under a decade of political turmoil.