Thomas Johnstone (sometimes called Tom Johnson) (1772 – 1839), commonly known as Johnstone the Smuggler or the Hampshire Smuggler, was a British sailor, smuggler and Admiralty saboteur. Writing in 1823 biographer John Brown described Johnstone as a real-life Rob Roy. Johnstone began smuggling aged 15, fought against the French in the Napoleonic Wars as a privateer, operated as a British double agent and led teams of divers to plant explosives on enemy shipping and fortifications. He also commanded both HMC Fox (a Revenue Cutter) and the first practical submarine, Nautilus.