Queen Elizabeth II was a long-serving constitutional monarch of the United Kingdom. In 1981, the Queen was targeted for assassination by the Irish Republican Army when she visited the Shetland Islands to commemorate the opening of an oil terminal. Finbar and Patrick Duggan were responsible for handling the explosives used in the attempt. However, the information provided to them was faulty, resulting in the failure of the mission and the arrest of nearly all of their associates. (Operation Hell Gate) See also Charles and Diana.