LONDON — The U.K. Supreme Court ruled Wednesday that Scotland does not have the power to hold a new referendum on independence without the consent of the British government. The judgment is a setback for the Scottish government’s campaign to break away from the United Kingdom. The top court ruled that the Scottish Parliament “does not have the power to legislate for a referendum on Scottish independence.” Supreme Court President Robert Reed said the five justices were unanimous in the verdict, delivered six weeks after lawyers for the pro-independence Scottish administration and the Conservative U.K.