Jack the Ripper is the best-known name given to an unidentified serial killer who was active in the largely impoverished areas in and around the Whitechapel district of London in 1888. In real life, the killer was never caught and the identity of Jack the Ripper remains unconfirmed, though there are numerous suspects.
In the Whoniverse, Jack the Ripper has been invoked in a number of stories, such as the Fourth Doctor story "The Talons of Weng-Chiang" where the villain was blamed for the murders. In the Eleventh Doctor comic story "Ripper's Curse" (IDW comic story), the killer was revealed to be an alien war criminal Doctor defeated. The Seventh Doctor novel "The Pit" (Virgin New Adventures novel) blamed it on a cult, while a different Seventh Doctor novel, "Matrix" (BBC Past Doctor Adventures novel), indicated the Valeyard was responsible. Several audio dramas have also referenced the killer.
The Eleventh Doctor episode "A Good Man Goes to War" contradicts most of the above by suggesting Madame Vastra not only apprehended Jack the Ripper, but she proceeded to eat him, though whether she really did is at present unknown. The later episode "The Name of the Doctor" has Vastra encountering a serial killer of women who, while never referred to as Jack the Ripper, nonetheless has similarities to the classic depiction of the villain.