The Number Ten operation is getting stronger by the day. Downing Street will announce tomorrow the appointment of WPP's David Muir as Director of Political Strategy. Regarded as one of Sir Martin Sorrell's right hand men, he has been CEO since 2005 of WPP's unit The Channel, which brings together the company's media and research skills, and (probably a must-read now for Brown watchers) the co-author of a well-received book called The Business of Brands. He is also on the Advisory Board of the John Smith Memorial Trust. So soon after the arrival of Stephen Carter from Brunswick this marks another top capture for Team Brown, and is further evidence of the gear change I referred to in the Sunday Telegraph at the weekend.