Irish President Michael Higgins was welcomed in London on Tuesday by Prince Charles and his wife Camilla, as the first official visit to Britain by an Irish head of state got under way, dpa reported. The four-day visit comes more than 90 years after Ireland effectively became independent from Britain, and follows Queen Elizabeth II's historic first trip to Ireland in 2011. Relations have been transformed since the signing of the 1998 Good Friday Agreement, which ended decades of conflict in the British province of Northern Ireland.