His grandson Sir Henry Mildmay served as MP and was Master of the Jewel House for Charles I. Henry was critical of the king's religious policies, supported Parliament during the civil wars and attended the king's trial. After the Restoration Henry was arrested for his part in the regicide, but granted leniency because he had refused to sign the king's death warrant. Instead of the death penalty he was sent to the Tower of London, stripped of his knighthood and his estates and sentenced to life imprisonment.