The US government suspected that a mole inside the FBI was passing secrets to Irish republican militants who repeatedly plotted to assassinate Margaret Thatcher in the 1980s and 90s, files released to the Guardian showed on Monday.
A series of investigations by federal agents into alleged plots to murder Thatcher during visits to the US are detailed in hundreds of pages of FBI files involving the former prime minister, which were made public following a freedom of information request made after her death.