Two hundred years ago, on Sunday, 23 February, 1820, the Cato Street conspiracy was stopped in is tracks by one of the most reactionary governments in British history. Led by a former militia officer named Arthur Thistlewood, its ambitious aim was to overthrow the Britihs state, something nobody had attempted since Guy Fawkes in 1605, and something not tried again seriously until the IRA’s attempt to destroy Margaret Thatcher’s cabinet at the Grand Hotel in Brighton in 1984. Both attempts failed, but the infamous words of the IRA remind us that terrorists only have to be lucky once to succeed. The government of Lord Liverpool in 1820 did not need luck to foil Thistlewood’s plot, as they had in fact instigated the whole thing themselves so that they could incriminate as many of the radical forces as they could in one deadly trap. Coincidentally, Edwards the spy’s first suggestion to Thistlewood was Gunpowder Plot 2.0 to succeed where Fawkes failed by blowing up both he House of Commons and Lord Liverpool’s cabinet.