The Mail’s Kirsty Walker is leaving the Lobby to become associate director at the spinshop best known for Boris’ 2008 mayoral election campaign. Fleet Street’s first ever drugs correspondent is quitting the Mail after 12 years to take up the post at InHouse Communications. She tweets that she’s “ready for a new challenge”. Apparently her new job will require her to be well-versed in crisis management. No one mention injunctions…