He is portrayed by Terence Harvey.
After having been tasked with returning the prince to the palace and getting rid of the prostitute he married, Ann, Kidney and his men set out. Recognizing the prince's driver, Kidney ambushes him from behind, holding a knife to his throat. He tells the man that his charge will come sooner than expected and tells him to be a good man and drive him home quickly and quietly. He and his men then burst into the room where Prince Albert is having sex with Ann. His men grab Ann and drag her into a coach waiting outside, much to the protest of Albert and Ann. Albert asks Kidney what this is supposed to mean, but Kidney ignores him, instead ordering his men to trash the room. Albert is then put into his coach and driven off, supposedly back to the palace. Kidney then interrogates Ann to find out who knows about Albert's affiliation with Ann. Ann eventually gives up her friends, causing the Freemasons to send one of them, Sir William Gull, to create the personna of Jack the Ripper to murder the prostitutes who know too much. When Inspector Abberline, who is investigating the Ripper murders, asks the prostitute Mary Kelly, a friend of Ann who witnessed her abduction, what she remembers of the night where the first prostitute was murdered, Mary Kelly describes Benjamin Kidney to him. Though his friend and colleague Sergeant Peter Godley advises Abberline against it, Abberline infiltrates Kidney's office. There, Abberline looks through Kidney's files until he finds out that Ann has been brought to a sanatory and that her child has been put into an orphanage. While waiting for Abberline's return, Godley sees that Kidney's carriage is arriving. To warn Abberline and stop Kidney, Godley ignites a barrel full of gunpowder and kicks it towards Kidney. Though no one is hurt, Abberline can escape in the chaos without being seen by Kidney.
Kidney attends a freemason meeting, where dr. ferral is initiated to the order. There, he talks to Abberline's superior Warren, who also is a freemason. They talk about Abberline. Kidney then sends three of his men to Abberline, who ambush him in an alley and tell him to find a scapegoat for the killings.
When Abberline, determined to find out the truth, realises that the Freemasons are behind the murders and that Sir William Gull is Jack the Ripper, he heads to Sir William's house to kill him, knowing that the Freemasons would never allow Gull to be imprisoned. However, before he can kill Gull he is knocked out by Kidney, wo had followed him. Kidney and Dr. Ferral then take Abberline into a carriage, where Ferral tries to inject him with a lethat dose of opium. However, Abberline rams his whole body into Ferral, knocking him unconscious when hes head hits the carriage's window. Kidney then tries to threottle Abberline but the inspector kicks him into the stomach, causing Kidney to fall back, now hanging out of the window. When Kidney's head get's between the wheels the wheels break, causing the entire carriage to topple over, landing on top of Kidney who is smashed by the weight. The horses then panick, carrying the wreckage further, with Kidney's corpse still jammed underneath.