M.R. James Ghost Stories – 2005 to 2010 – This collection is made up of three ghost story adaptations: Whistle and I'll Come to You, A View from a Hill, and Number 13.
Mad Dogs – 2011 to 2013 – John Simm and Philip Glenister (both of Life on Mars) reunite alongside Max Beesley and Marc Warren in this psychological thriller about old friends gathering in Spain and getting caught up in a world of corruption.
Maelstrom – 1985 – Shortly after being made redundant, an English woman learns she's been left a fortune in Norway, but her efforts to figure out lead to bad things.
Maigret – 1992 to 1993 – Maigret keeps his sense of humor as he examines the dark motives behind the crimes.
Maigret – 2016 to 2018 – Rowan Atkinson stars in this adaptation of the popular French detective.
Malice Aforethought – 1979 – A doctor believes he has committed the perfect murder of his wife.
Man in a Suitcase – 1967 to 1968 – A US agent is thrown out of the agency for something he didn't do, so he travels around Europe working as a PI and trying to clear his name.
Manhunt – 2018 to present – This crime drama is based on the real-life capture of serial killer Levi Bellfield.
Marcella – 2016 to present – After Marcella leaves her job as a detective to concentrate on family, her husband leaves her for another woman and she decides to return to the force.
Marchlands – 2011 – Jodie Whittaker (Doctor Who, Broadchurch) stars in this miniseries set at three different points in time at one haunted house.
Masterpiece Mystery – 1980 to 2016 – This weekly anthology program offers British mysteries for the American public, featuring Vincent Price, Diana Rigg, Gene Shalit, and Alan Cumming as hosts.
Mayday – 2013 – When the May Queen disappears just before May Day celebrations, a small town is thrown into chaos.
McCallum – 1995 to 1998 – Pathologist McCallum and his team help the dead tell their stories.
McCready & Daughter – 2001 – Ireland – When his daughter drops out of university, she joins her father as a private investigator in an Irish community.
Messiah – 2001 to 2008 – This miniseries collection features Ken Stott leading a team of serial killer investigators, but later switches to Marc Warren.
MI-5 aka Spooks – 2002 to 2011 – This dramatic series follows top secret missions of the MI-5, the UK's elite domestic security and counter-intelligence agency.
Midsomer Murders – 1997 to 2018 – DCI Barnaby solves murders in the not-so-peaceful British countryside.
Midwinter of the Spirit – 2015 – Country Vicar Merrily Watkins consults on a murder investigation and gets on-the-job training in exorcism.
Miss Fisher's Murder Mysteries – 2012 to 2015 – In the 1920s, Miss Phryne Fisher works as a skilled private detective.
Miss Marple – 2004 to 2014 – In the small village of St. Mary Mead, Miss Marple helps her community by solving murders.
Missing – 2009 to 2010 – In a busy missing persons unit, DS Mary Croft leads a determined but under-resourced team.
Mitch – 1984 to 1984 – John Thaw (Inspector Morse) stars as a reporter who covers the most unsavory of crimes.
Moses Jones – 2009 – A body found in the Thames seems to be related to witchcraft.
Mother Love – 1989 to 1989 – An otherwise pleasant marriage turns ugly when a jealous mother-in-law gets in the middle of things.
Mr. and Mrs. Murder – 2013 – Australia – A married couple runs an industrial cleaning business while also solving murders.
Mr. Palfrey of Westminster – 1984 to 1985 – Mr. Palfrey seems to be a typical, mild-mannered government employee, but he's actually a spook.
Mrs. Bradley Mysteries – 1998 to 2000 – Diana Rigg stars as Mrs. Bradley, a sort of edgy Miss Marple who solves mysteries with the assistance of her devoted chauffeur.
Murder – 2012 to 2016 – This unusually-filmed series shows the events up to and after a number of different murders, with each episode offering a self-contained story.
Murder City – 2005 to 2006 – Kris Marshall (Death in Paradise) stars in this series about two mismatched London detectives who solve complicated cases.
Murder in Mind – 2001 to 2003 – Each episode in this anthology series features a murder from the killer's perspective.
Murder in Suburbia – 2004 to 2005 – Posh Ash and working-class Scribbs solve murders in the fictional suburban town of Middleford.
Murder in Successville – 2015 to 2017 – Each episode features a celebrity teamed with DI Sleet to investigate a crime in a town filled that’s also filled with celebrities.
Murder Investigation Team – 2003 to 2005 – A London-based team of elite investigators handles exceptionally challenging murders.
Murder Most English: The Flaxborough Chronicles – 1977 – This 1970s detective series is based on the Flaxborough novels by Colin Watson.
Murder Most Horrid – 1991 to 1999 – In each episode, the lead actress plays a different character investigating a different murder, written by a different writer.
Murder on the Homefront – 2013 – This two-part miniseries follows a doctor and his receptionist as they investigate a serial killer in the midst of the blitz.
Murderland – 2009 – This miniseries looks at a murder from the perspectives of the daughter, the detective, and the murder victim.
Murdoch Mysteries – 2008 to present – Canada – Set in the 1890s, Murdoch uses early forensics to solve murders.
Murphy's Law – 2001 to 2007 – James Nesbitt (Cold Feet) stars as Tommy Murphy, a charming but tough Northern Irish cop with a tragic past.
My Cousin Rachel – 1983 – Based on the Daphne du Maurier novel, a man becomes convinced his wife has murdered his friend.
Mystery Road – 2018 to present – Australia – Detective Jay Swan investigates crimes in the Australian Outback.
New Blood – 2016 to present – Two young investigators are brought together by cases that initially appear unrelated.
New Scotland Yard – 1972 to 1974 – Two detectives solve the big cases for the New Scotland Yard.
New Tricks – 2003 to 2015 – Retired police officers are called back to investigate old cold cases.
No Offence – 2015 to present – This gritty Manchester-based police drama showcases the work of investigators under straight-talking DI Viv Deering.
Nobody's House – 1976 – Two children move into an old Victorian house with their parents, and only they can see its ghostly inhabitant.
One of Us – 2016 – In a remote Scottish Village, childhood sweethearts are found murdered after returning home from their honeymoon.
Ordeal by Innocence – 2018 – This three-part drama is based on the Agatha Christie novel of the same name.
Our Friends in the North – 1996 – This miniseries follows four friends from the heady 60s to the not-so-certain 90s.
Out – 1978 – After doing time for a bank robbery gone wrong, Frank will stop at nothing to find out who got him sent to jail.
Out of the Blue – 1995 to 1996 – Neil Dudgeon and John Hannah star in this gritty drama about a group of police at Brazen Gate CID.