Between Despard and Brandreth there stretches the illegal tradition. It is a tradition which will never be rescued from its obscurity. But we may approach it from three directions: first, from considering some surviving evidence as to the ‘underground’ between 1800 and 1802; second, from some criticism of the historical sources; and, third, from some examination of the quasi-legal trade union tradition. Unless we make this preparation, we shall be unable to understand the Luddite. movement, and the post-war years of the Pentridge Rising, Oliver the Spy, and the Cato Street Conspiracy.