JP were the initials of John Piggott of Cheapside, London, who produced a motorcycle early in 1913.
This machine had a 2.75hp engine, belt drive and sprung forks. There was also the option of a hub gear.
The JP, the “Impregnable Motorcycle” was displayed and listed until the middle of 1914, the outbreak of World War I stopped production.
Thanks to Dave Richmond for the 1913 advert