In 1983 letter bombs were sent to the Ministry of Defence, oil companies and public figures including Lady Diana Spencer and the Prime Minister, Margaret Thatcher. The device sent to Thatcher was active and was opened by parliamentarian Robert Key but there was no explosion. Busby fled to Dublin after the letter-bombing campaign. He reportedly tried to join forces with the Provisional Irish Republican Army, but the offer is said to have been refused. He organised attacks from Dublin involving anthrax hoaxes, bomb threats, and genuine parcel bombs.