She was portrayed by Daisy Beaumont, and voiced by Sally Grace in the radio series.
While shopping at a garden centre in Dembley she came across James and Agatha, unaware that they were undercover as a couple on an investigation. Subsequently, she made dinner plans with James at the local pub. In order to keep up her alias, Agatha gatecrashed Mary and James' dinner, causing a scene as she accused James of cheating on her - much to Mary's confusion. Annoyed and insulted, Mary stormed out. James later explained the situation and sent flowers to Mary as an apology, which she happily accepted. (TV: The Walkers of Dembley)
As with many of the Carsely locals, Mary was not impressed with the village's new bell ringing group. Mary, along with James, later joined the group following the death of Amanda Ballard. (TV: Hell's Bells)
After the news of Parish Council chairman Robert Struthers' death, Mary and James teamed up to investigate the potential murder due to James' past connection with the deceased. Mary's competitive nature quickly came out as she raced to solve the case, often behaving brash and blunt when she questioned suspects. This made her rather unpopular among the Ancombe locals. (TV: The Wellspring of Death)
Mary was known to be an extremely competitive person, for example when competing with James to solve the murder case in Ancombe or taking part in Carsely's garden show. (TV: The Wellspring of Death, The Potted Gardener)
- In the Agatha Raisin television series, Mary was notably introduced before the show's adaptation of Agatha Raisin and the Potted Gardener. This allowed for Mary's character to be explored slightly further than in the books and made her murder halfway through the first season all the more shocking.