Tamasin Elizabeth Berry-Hart was born in Warwickshire, England, and writes for adults, young adults and children. Her novels and plays deal with themes such as the future, science fiction, genetic engineering, environmental issues, LGBT issues, mental illness and existentialism. She has also written some verbatim theatre pieces for stage to support human rights campaigns.
Tess Berry-Hart is the daughter of painter and sculptor David Berry-Hart. Her grandmother, Alice Berry-Hart, was a journalist and author of children’s books and her aunt Marian Lines was a playwright and children's author. Berry-Hart attended Weddington Primary and Weddington Secondary Schools, and from age 11 to 18, she studied at Howell’s School, Denbigh. In 1993 she spent a year travelling and working in Turkey and Pakistan's North West Frontier as a teacher of English. In 1997 she graduated magna cum laude with a first-class degree in law from King's College London.
In 1999 she studied at the Royal Court Theatre Young Writers’ Programme under the tutorship of Hanif Kureishi and Simon Stephens. In 2000 she was selected to be the Royal Court young writing representative at the Interplay Young European Playwrights Festival with her first play Legoland. In 2001 her short play Jack was performed as part of the Royal Court’s Under The Skin festival. From 2003–2005 she was the writer in residence at the Blue Elephant Theatre, London, where her play Waking Up Suddenly was performed. In 2007 her first novel, Escape from Genopolis, was published. This was followed by her sequel, Fearless, in 2009. She returned to the theatre stage in 2012 with a verbatim piece, "Someone To Blame" which was based on the real-life case of Sam Hallam, a teenager wrongfully convicted of murder and imprisoned for 7 years. In 2014, she was commissioned by the King's Head Theatre in London to write a play about the lives of LGBT Russians following the passing of the anti-gay laws in Russia ahead of the Winter Olympics. "Sochi 2014" was performed at the King's Head's new writing venue, The Hope Theatre London, in 2014, with similar benefit performances in New York and Los Angeles. An updated version of Sochi 2014 was produced and won an NSDF commendation award at the Edinburgh Festival, during August 2014.