The series is based on the Tony Hill and Carol Jordan novels by Scottish writer Val McDermid, though only four episodes across the show's run were directly adapted from her books, with the rest being original stories written for television.

ITV cancelled the series in 2009, citing high production costs estimated at up to £750,000 per episode as well as competition from numerous new series being broadcast on the network.

Actor Robson Green conducted his own research for the role of Dr. Tony Hill by spending time with real-life criminal psychologist Julian Boon, whom he described as an 'extraordinary, intelligent, nice guy who carried his life in a blue bag and traveled on a double-decker bus.'

Green adopted the prop of a plastic 'blue bag' directly from Boon's practice as part of his character's look.

Hermione Norris left the series after series 3 when she took on the role of Ros Myers in Spooks, leading her character Carol Jordan to be written out as having emigrated to South Africa; Simone Lahbib joined as her replacement, DI Alex Fielding.

Series 1 was filmed between 22 October 2001 and 14 February 2002 around Newcastle upon Tyne, Durham and Northumberland, using locations such as Bollyhope Quarry, Chopwell Woods, and Eshott Hall, which served as the Vance residence.

Series 2 was filmed in and around Newcastle, notably using the old Bank of England building on Pilgrim Street as its main location, along with Finchale Priory, Durham Cathedral, and Calder's Brewery near the Newcastle Arena.

The series 5 episode 'Prayer of the Bone' was filmed in and around Austin and La Grange, Texas in the United States, a departure from the show's usual UK filming locations.