At the start of the year, Irish state papers, released under the 30-year rule, revealed documents relating to a purported attempt by British security agency MI5 to use the UVF (pro-British paramilitaries) to assassinate Charlie Haughey, the Irish Taoiseach (Prime Minister) in 1987. The letter, send to the Irish government on UVF headed paper, and believed at the time to be genuine said that the UVF had refused: “We have no love for you but we are not going to carry out work for the Dirty Tricks Department of the British.” The Irish Times The Guardian

What is the historical consensus, if any, on this incident? Was the assassination by proxy of the leader of another country an unprecedented action by British security services? Did other states carry out such operations?