After reading English at Liverpool University, Thomas gained national attention when her play, Shamrocks And Crocodiles, won the John Whiting Award in 1985. Her play Indigo was performed by the Royal Shakespeare Company in their 1987/88 season. Other theatrical work includes Some Singing Blood at London's Royal Court Theatre, and an adaptation of Ibsen's The Lady from the Sea, presented in London and at the National Theatre of Norway in Oslo. Her play The House of Special Purpose was staged at the Chichester Festival Theatre in 2010. Her screen adaptations include feature filmI Capture the Castle and the screenplay for a BBC television adaptation of Madame Bovary. In 2007 she was the creator, writer and executive producer of BBC period dramaLilies. She wrote the screenplays for two major BBC adaptations of Elizabeth Gaskell's Cranford, and a film adaptation of the Noel Streatfeild novel Ballet Shoes. In 2010 she was writer and executive producer of a major revival of the classic British television drama seriesUpstairs, Downstairs for the BBC. In 2011 she wrote and co-produced an adaptation of the Call the Midwife trilogy of books by Jennifer Worth. The series achieved record viewing figures for the channel. A second and third series aired in subsequent years. In February 2014 BBC announced that a 2014 Christmas Special and a fourth series had been commissioned. A fifth series was commissioned for 2016, shortly after series four was done filming. On 23 November 2016, the BBC announced a three-year deal with Neal Street Productions, commissioning a seventh, eighth and ninth series, all with Christmas specials. The new commission will keep the series on air until at least 2020. In March 2008, she received the Best Writer award at the UK Royal Television Society awards for her work on Cranford. In April 2008 she received the Best Writer award at the UK Broadcasting Press Guild Awards for her work on Cranford, Ballet Shoes, and Lilies. She was nominated for two BAFTA TV Awards for Cranford as well as a Primetime Emmy. In November 2008 she received the Writers' Guild of Great Britain award for Best TV Series for Cranford. In 2011 she received a Primetime Emmy nomination for Upstairs Downstairs. In December 2012, the annual UK 'Women in Film and Television' awards presented her with the Technicolor Writing Award in recognition of her contribution to the industry. A production of the musical Gigi was newly adapted by Thomas and ran at the Kennedy Center in January 2015, and then on Broadway, closing in June 2015. In January 2019, Thomas was presented with the Outstanding Contribution to Writing Award by the Writers' Guild of Great Britain for her body of professional work. Thomas has honorary doctorates from the University of Liverpool and Edge Hill University
Family
Thomas is married to actor Stephen McGann, who plays Dr Turner in Call the Midwife, with whom she has a son, Dominic.