Foreign Secretary Boris Johnson will meet with key congressional leaders in Washington on Monday as the U.K. seeks to strengthen ties with Donald Trump’s incoming administration a day after Prime Minister Theresa May signaled Britain may quit the European Union single market. The pound fell to a 10-week low after May said in a Sky News television interview on Sunday that leaving the EU will be about “getting the right relationship, not about keeping bits of membership,” suggesting Britain may opt for a so-called hard Brexit.