Ryzt

Lord Ryzt led an attempted invasion of Earth in 1912. Taking over the household of Lord Cranarch just before the Doctor was due to arrive for dinner. They used their ‘dullifiers’ to hypnotise and drain the memories of their hosts. Lord Cranarch once held a position high in British intelligence and so would have given away secrets of the defence of the country. The Doctor intervened and turned the alien technology against the aliens persuading them that Earth wasn’t worth bothering about and that they should return home. (DWA: The Demons of Repton Abbey)