Theresa May offered her strongest support yet for London’s financial district, insisting that banks are of “huge value” to the U.K. economy as executives signaled they were accelerating plans to move staff abroad after Brexit. “I value financial services in the City of London, and I want to ensure that we can keep financial services in the City of London,” the prime minister said in an interview with Bloomberg editor-in-chief John Micklethwait at the World Economic Forum in Davos, Switzerland, on Thursday.