Case file · Series 23, Episode 3 · Season 23, Episode 3
A Grain of Truth
An organic bakery divides its village before a mass poisoning and two attacks make the dispute impossible to dismiss.
Verified filming locations
Every filming site currently documented in this Casebook file is listed here. The published evidence does not establish a complete production itinerary.
- Mapledurham Watermill · Mapledurham, Oxfordshire
The historic watermill appears as Larkton's Mill and its organic bakery.
Location guide → Filming source ↗ - The Highway Inn · Checkendon, Oxfordshire
The real pub keeps its name as The Highway Inn in fictional Lower Blissingham.
Filming source ↗
Map lookup by place name. A private house’s exact address is not marked.
Selected episode credits
A Grain of Truth cast
These selected cast entries link to their published profiles. They do not include every name shown in the end credits.
Fiona Dolman
Laila Rouass
Rebecca Night
Jo Martin
Robert Gilbert
Paul Chahidi
Harry Taurasi
Natasha Atherton
Jola Jassy
Flaminia Cinque
Russell Floyd
Martin Trenaman
Geoffrey Lumb
Chris Coniston
The 60-second case card
Should I watch this one?
A recognisable argument about development and food culture becomes a careful mystery about who is being protected—and from whom.
- Best for
- Artisan bakery · Village dispute · Poisoning
- Mood
- Classic
- Team
- DCI John Barnaby with DS Jamie Winter
- Spoiler guidance
- Read the premise freely; open the marked sections only after watching. Check the linked provider advisory for further viewing information.
Why it matters
A recognisable argument about development and food culture becomes a careful mystery about who is being protected—and from whom.
Tom and Chrissie Larkton have transformed the old mill into a fashionable organic bakery, attracting customers and resentment in equal measure. A threatening cake and a broken farming contract appear to be acts of protest until people at the village pub are dosed with a dangerous hallucinogen.
A local supplier is then murdered, an attendee at Tom's course is using a false name, and another man is lured to his death. Barnaby and Winter look past the public campaign against the bakery to determine why several victims pose a threat to the same person.
Break the seal: reveal the finding
Who was the killer in A Grain of Truth? (spoiler)
The killer's choices are governed by a desire to shield someone from renewed harm, and the bakery feud provides a noisy public explanation for much more personal acts.
More episode detailsProduction, cast, deaths and filming information
Credits, context and checked facts
Production and cast
- TV series
- Series 23
- Episode number
- Episode 3
- Written by
- Julia Gilbert
- Directed by
- Paul Gibson
- Listed transmission date(s)
- 26 December 2022 23 July 2024
- Reported filming period
- May–June 2022
- Detective
- DCI John Barnaby
- Partner
- DS Jamie Winter
- Pathologist
- Dr Fleur Perkins · Annette Badland
- Principal setting
- Lower Blissingham
- Casebook tone
- Classic
Sources accompany the production credits and filming links.
Fictional settings and real filming places are listed separately. Filming links include 1 mapped area; 2 exact sites.
Credits and archive connections
- Writer credits7 episodes credited to Julia Gilbert
- Director credits3 episodes directed by Paul Gibson
- Release positionCase 135 of 144
- Story characterClassic · Artisan bakery · Village dispute
- Location evidence2 exact screen-use matches
Mapledurham Watermill becomes Larkton's Mill and gives the bakery its working riverside exterior.
The Highway Inn at Checkendon appears as The Highway Inn in fictional Lower Blissingham.
Sources for the production file
Published episode chronology and credits ↗Official ITV programme page ↗Filming-location reference index ↗Credits follow the linked chronology. Dates can differ between territories. Consult original credits for story, teleplay and adaptation wording. External synopses may contain spoilers.
The performers behind this case
Core cast
Follow the cast links for full actor and character guides.
Neil Dudgeon
John Barnaby · Detective Chief Inspector- Messiah
- Life of Riley
- The Mrs Bradley Mysteries
Nick Hendrix
Jamie Winter · Detective Sergeant- Black Mirror
- Marcella
- The Crown
Annette Badland
Dr Fleur Perkins · Police pathologist- Ted Lasso
- Doctor Who
- EastEnders
Image credits identify the licence used. No programme publicity stills are reproduced.
Forensic team
Dr Fleur Perkins
- Credit
- Resident pathologist
- Played by
- Annette Badland
Spoiler-controlled deaths
Deaths recorded in this case
2 people die in this case, according to the linked death record.
Break the seal: reveal the list of deaths
- Nathan Duncroft
Murder · Other recorded death
Performer check- Nathan Duncroft: Geoffrey Lumb
- Ricky Naybury
Murder · Crushing
Performer check- Ricky Naybury: Chris Coniston
Break a second seal: reveal the verified killer
Who was the killer in A Grain of Truth? (spoiler)
Gabriel ArnsonGabriel caused Michael Cignoni's historical death while defending Chrissie, then stopped her from rescuing Michael after his fall into the river and concealed what had happened. In the present day he suffocated Nathan Duncroft in the grain silo because he wrongly believed Nathan had planted the ergot, killed Ricky Naybury after Ricky tried to blackmail him with evidence from Michael's death, and tried to drag Tom Larkton into the millpond. Bobby Cignoni had planted the ergot, while Silas Bantrig abandoned his separate plan to contaminate the water.
Verified motive
Gabriel's lifelong fixation on protecting Chrissie began when he stopped her rescuing the predatory Michael after Michael's accidental fall, calling the death divine justice and exploiting Chrissie's amnesia to conceal it. He later killed Nathan in mistaken retaliation for the ergot that endangered her, killed Ricky to stop blackmail over Michael's death and attacked Tom as Chrissie's recovered memories threatened the secret.
Real place → fictional identity
Where was A Grain of Truth filmed?
Mapledurham Watermill
Used as: The historic watermill appears as Larkton's Mill and its organic bakery.
Representative photograph of the real filming location; the exact camera angle or building may differ.The Highway Inn
Used as: The real pub keeps its name as The Highway Inn in fictional Lower Blissingham.
Sources accompany the identified filming places.
Wider filming areas