Anna Maxwell Martin has been announced to play journalist and campaigner Heather Brooke , whose tenacious investigations brought about the disclosure of MPs' expenses, in one-off drama Bringing Down The House for BBC Four . Brian Cox will star opposite Anna as Speaker of the House of Commons Michael Martin, who was forced to resign after finding himself in a battle against Heather's determination for Freedom of Information relating to MPs' expenses and allowances. Written by Tony Saint , the humorous 60-minute drama will focus on the events leading up to one of the biggest political scandals in recent history, and reveal the David and Goliath tale behind the now infamous headlines. Bringing Down The House will also star Alex Jennings , as Fees Office head Andrew Walker, the man in charge of approving MPs expenses; Tim Pigott-Smith as Labour MP Alan Keen; and Neil Pearson as Hugh Tomlinson QC, who successfully led the legal campaign to force the Commons to publish