Harriet Walter as DI Natalie Chandler
Natalie Chandler is Ronnie Brooks and Matt Devlin's boss - Her job is to push her detectives, making sure they stay within the lines of propriety and to play devil's advocate to their investigations. Chandler is a great boss and a good people person. She leaves no uncertainty about who is in charge but she's fiercely loyal to Ronnie and Matt. As a working mum, Natalie knows how to motivate and how to discipline them and is always fair and focused.
Chandler also brings a sympathy and softer side to her detectives, considering their families even when they don't. Despite maintaining her emotionality, Chandler will be the one bastion of objectivity when all others cannot. She's able to be dispassionate when all around her are losing their heads.
Natalie has a huge heart and is extraordinarily empathetic - but she knows how and when to switch that off, for the good of the job and for the benefit of good, impartial police work.