Professor Horace Slughorn: The new Potions teacher at Hogwarts, who has secret knowledge regarding Lord Voldemort. Timothy Spall as Peter Pettigrew/Wormtail: The Death Eater who betrayed Harry's parents to Voldemort. Imelda Staunton as Dolores Umbridge: Senior Undersecretary to the Minister for Magic and Head of the Muggle-born Registration Commission. David Thewlis as Remus Lupin: A member of the Order of the Phoenix and a former teacher at Hogwarts. Natalia Tena as Nymphadora Tonks: Remus Lupin's wife and a member of the Order of the Phoenix. George Harris as Kingsley Shacklebolt: Another member of the Order of the Phoenix. Julie Walters as Molly Weasley: The Weasley matriarch and a mother figure to Harry. Mark Williams as Arthur Weasley: Ron Weasley's father, an Auror at the Ministry of Magic. Domhnall Gleeson as Bill Weasley: Arthur and Molly's eldest son who helps Harry to escape from Little Whinging and who is to marry Fleur. Clémence Poésy as Fleur Delacour: A French Witch of the Beauxbatons School who also helps Harry to escape from Little Whinging. Guy Henry as Pius Thicknesse: The puppet Minister of Magic installed by Voldemort. Peter Mullan as Corban Yaxley: A Death Eater at the Ministry of Magic. Carolyn Pickles as Charity Burbage: The Muggle Studies teacher at Hogwarts, tortured and killed by Voldemort. David Ryall as Elphias Doge: An old schoolfriend of Albus Dumbledore who defends him in an obituary. Richard Griffiths as Vernon Dursley: Harry's Muggle uncle. Fiona Shaw as Petunia Dursley: Harry's Muggle aunt. Hazel Douglas as Nagini: Voldemort's familiar snake, who puppeteers the corpse of Bathilda Bagshot. Production Part 1 was filmed back-to-back with Harry Potter and the Deathly Hallows – Part 2 from 19 February 2009 to 12 June 2010. Director David Yates, who shot the film alongside director of photography Eduardo Serra, described Part 1 as "quite real"; a "road movie" that's "almost like a vérité documentary". Originally set for a single theatrical release, the idea to split the book into two parts was suggested by executive producer Lionel Wigram due to what David Heyman called "creative imperative". Heyman initially responded negatively to the idea, but Wigram asked, "No, David. How are we going to do it?". After rereading the book and discussing it with screenwriter Steve Kloves, he agreed with the division. The production filmed at the Dartford Crossing for the dramatic chase where Harry and Hagrid are being ambushed by Death Eaters.