Simon Mark Arthur, 4th Baron Glenarthur, DL, is a British peer, pilot and businessman. Having succeeded to his father's titles in 1976, he is one of the ninety hereditary peers elected to remain in the House of Lords after the House of Lords Act 1999, and sits as a Conservative.

The Parliamentary Under-Secretary of State for Scotland is a junior ministerial post in the Government of the United Kingdom, supporting the Secretary of State for Scotland. The post is also known as Deputy Secretary of State for Scotland.