His services were too great to be neglected by the new Hanoverian king, and in 1714, he was created Earl of Clare, and in 1715 Duke of Newcastle-upon-Tyne, two titles previously held by his late uncle John Holles. He also became Lord-Lieutenant of the Counties of Middlesex and Nottingham and a Knight of the Garter. In his new position, he was in charge of suppressing Jacobitism in the counties under his control. In Middlesex, he arrested and questioned 800 people and drew up a Voluntary Defence Association to defend the county. In 1715, he became involved in a riot that ended with two men being killed, and Newcastle fleeing along rooftops. The succession of George I was secured in late 1715 by the defeat of a Jacobite army at the Battle of Preston and the subsequent flight of the Old Pretender.