Factual error: Chief Inspector Abberline's warrant card is signed by Commissioner Leonard Dunning. No Commissioner of the Metropolitan Police had this name or anything like it.
Factual error: Everyone celebrates the beginning of the new century at midnight on 31 December 1899. In fact, the beginning of the 20th century was celebrated (correctly) at midnight on 31 December 1900. In those days people still knew that a decade (and a century) begins with a year 1, not a year 0.