A massive security operation to protect the life of Pope John Paul II swung into action during his historic visit to Ireland amid concerns that he could be a terrorist target.
Just a month after the Queen's cousin Lord Louis Mountbatten was killed in an IRA explosion on his boat in Mullaghmore, Co Sligo, security officials warned of the possible risks of sniper or bomb attacks on the pontiff during his visit.
The Pope's arrival posed possibly the greatest logistical and security challenges ever faced by the State and came as the Troubles north of the border continued unabated.
Security briefing documents contained in newly released State Papers reveal how the Pope's plane faced the risk of sabotage, hijacking or an attack on the pontiff himself during his flight from Rome in September 1979.
A briefing document marked secret and sent to the Garda Commissioner raised the risk of direct sniper and bomb attacks at Dublin airport, the Papal nunciature and at the Phoenix Park, where a million people gathered to watch the Pope celebrate Mass.
Despite this, gardai ruled out using bullet-proof glass in vehicles carrying the Pope. A security risk assessment in September 1979 claimed no measures could protect the Pontiff if “desperate persons” planned an assassination.
“The unanimous opinion of the officers involved in co-ordinating operational and security matters was that bullet-proof glass should not be used,” the document stated.
It later added: “It must be borne in mind, however, that if desperate persons plan to kill the Pope, then no security measures which the gardai could implement would guarantee the Pope's safety.
“There is no such thing as absolute security.”
The Irish government was also concerned republicans might try to attend a function with the Pope.
“(Such a meeting would) lead to a reaction of extreme anger among the Protestant community in Northern Ireland, with the consequent grave danger of sectarian murders, bombings, and other outrages, north and south of the border in Ireland,” the memo read.
As the security headache concentrated the minds of Irish officials, the Pope's visit had a serious political dimension with speculation of whether he would visit Northern Ireland.
One Foreign Affairs file reveals how the British Government would be glad to co-operate should he wish to visit Northern Ireland but hoped he would not come via the “back door” from the Republic.
In the end, the Pope never did cross the border — the closest he came was Drogheda.