From Wikipedia, the free encyclopedia. Laura Greenwood (born 1991) is an English actress and a member of the YoungBlood Theatre Company in 2006. Greenwood's big breakthrough came in 2006 when at age 14 she starred as Penny Philips opposite Helen Mirren in Prime Suspect The Final Act, the two-part conclusion to ITV's long-running series. Critics praised her work in the drama, with David Bianculli of the New York Daily News writing, "The scenes she shares with Mirren are nothing short of phenomen ...