Heidi Thomas is a British screenwriter and playwright, known for the TV and film adaptions of "Madame Bovary" (2000), "I Capture the Castle" (2003), "Ballet Shoes" (2007) and "Cranford" (2007-2009), as well as the creation of the BBC TV series "Lillies" (2007), "Upstairs Downstairs" (2010) and "Call the Midwife" (2012 - ).