WASHINGTON (Reuters) -The United States and the United Kingdom will kick off trade talks next week, the U.S. Office of the Trade Representative (USTR) and the British government said on Wednesday. Securing a trade deal with the United States was one of the main goals of the campaign that led Britain out of the European Union, although critics said any deal would take years and never fully compensate for leaving the EU’s single market. Discussions will start March 21 and March 22 in Baltimore, Md., followed by another meeting later in the spring in Britain, the two sides said in separate statem…