There would be little debate in the House of Commons if everyone agreed with what the government wanted to do. But every Parliament has Members who disagree strongly with the government in power. They usually are the Opposition. The phrase "Her Majesty's Loyal Opposition" grew out of the traditions of British government. It means that those who form the official Opposition must still remain loyal to the monarch and to the practises and procedures of Parliament, no matter how much they disagree with the government.
