For beginners, 'Case Histories' by Kate Atkinson is a wonderful choice. It combines multiple mysteries in one story and is written in a very accessible style. The characters are well - drawn and the plots are engaging. 'The Ice House' by Minette Walters is also good. It's about a woman who discovers a body in an ice house on her property. The mystery unfolds slowly, which is great for those new to the genre as they can follow along easily. And 'The Suspicions of Mr Whicher' by Kate Summerscale is based on a true crime case and is a very interesting read for those starting to explore British crime novels.
If you're new to British crime novels, 'The Talented Mr Ripley' by Patricia Highsmith (although she's American, the book has been highly influential in the British crime genre) is a great start. It has a complex anti - hero and a thrilling plot. 'The Innocent Man' by John Grisham (again, not strictly British but has had an impact on the genre here) is also a good option. It's about a man wrongly accused of a crime. And 'The Bone Collector' by Jeffery Deaver (who has influenced British crime writing) is a page - turner with a detective who is paralyzed but still manages to solve crimes. These books can introduce you to the elements of the British crime novel genre.