star Gemma Whelan will star in a three-part police drama from the writer of .
ITV's, based on , the first book in author Kate London's Metropolitan series, will feature Whelan as Detective Sergeant Sarah Collins.
She is charged with investigating after a veteran beat cop and teenage girl fall to their deaths from a tower block in south-east London, leaving a five-year-old boy and rookie police officer Lizzie Griffiths on the roof. Within hours, both have gone missing and Collins sets out in search of them, while trying to uncover the truth behind the deadly fall.
Whelan, 39, played the ruthless Yara Greyjoy in HBO fantasy epic. She also featured as Karen Matthews in and Marian Lister in hit BBC drama . Her other recent credits include , , and .
Filming will begin later in April and further casting details, including for the part of Griffiths, will be announced in due course.
is adapted by Patrick Harbinson, who wrote and executive produced US spy drama , starring Damian Lewis as a US double agent. He also serves as executive producer alongside Mammoth Screen's founder and chief executive Damien Timmer ( , ) and Karen Thrussell ( , ).
Author London is a former Metropolitan Police officer who finished her career working as part of a major investigation team on the homicide and serious crime command.was her first novel.