Even after 150 years, the grisly murder of a three-year-old boy at a Wiltshire county house has retained the ability to shock and mystify in equal measures.

Perhaps it is because many feel the case was never truly solved, or maybe it is because the brutal slaying of Saville Kent at Road Hill House, near Trowbridge, was the first real Victorian whodunnit, capturing the imaginations of authors such as Charles Dickens and Arthur Conan Doyle.

Brought back to modern minds by Kate Summerscale’s award-winning book The Suspicions of Mr Whicher, the Rode Hill House case has caught the imagination of local historian Andrew Jones, who will host a talk on his theories about the murder on July 2 – two days after the 150th anniversary.

Coincidentally the gated grounds of Rode Hill House, now Langham House, will be opened to the public by its current occupants, Chris and Steph Lyons, on July 4 from 2-5pm for an open garden event raising money for the village church.

It was on the night of June 29/30, 1860 that Saville Kent – one of three children from his father Samuel’s second marriage – was taken from his bed.

He was found the next day suffocated and with his throat slashed. His body was balanced on a splashboard in a privy, within the grounds.

Suspicion fell on every member of the household, including the remaining family members and servants, but it wasn’t until five years later that Saville’s half-sister Constance confessed to the murder.

Mr Jones, 49, of Innox Road, will host his talk about the murder at Roundstone Prep School, in Polebarn Road, Trowbridge, from 7.30pm.

He said: “The first time I came across the case was a BBC series in the 1980s called Cruelly Murdered. I have read all the books since.

“I believe the case is unsolved. Constance’s confession of 1886 just doesn’t hold water.

“I have my own theories and supporting evidence that I don’t believe anyone else has picked up on, which I will reveal at my talk.”

Mr Jones, a caretaker at John of Gaunt School in Trowbridge and a lay Baptist preacher, will also host a guided walk around Rode on July 25 from 3pm. He is also writing a book on the murder for Trowbridge Museum.