Town Police Clauses Act of 1847
Under the Town Police Clauses Act of 1847 it is an offence for any person in any street: to let an unmuzzled ferocious dog be at large so that it obstructs or annoys the residents or passengers in the street or puts them in danger; or to set on or to urge any dog to attack, worry or put in fear any person or animal. A dog will not be at large while it is held on a lead. The word 'street' here is given an extended meaning to include any road, square, court, alley, thoroughfare or public passage.
In the Metropolitan Police District a similar offence has been created by the Metropolitan Police Act of 1839. This differs only from the first part of the 1847 Act offence in that it is sufficient that an unmuzzled dog be at large (no obstruction, annoyance or danger need be shown), and that the place of the offence is described as any thoroughfare or public place.