It was in the mid-1980s that Colonel Gaddafi's Libyan regime supplied the IRA with huge amounts of weaponry and explosives which transformed the organisation's capacity for violence.
Four separate shipments of arms made their way from Libya to Ireland in the mid-1980s, providing the IRA with around a thousand Kalashnikov rifles, Semtex plastic explosive, heavy machine guns, Sam-7 missiles and anti-aircraft guns capable of downing helicopters and planes, and even flame-throwers.
Gaddadi seemed motivated not so much by any strong sympathy for the IRA as by a sense that he wanted to harm Britain as much as possible.
The authorities were initially jubilant when, in November 1987, a French customs patrol intercepted a battered trawler named the Eksund off the coast of Brittany and found on board a large amount of weaponry.
But celebrations in London and Dublin turned to dismay when a member of the crew disclosed under interrogation that four previous shipments had got through.
The authorities were shocked and appalled, for it meant the threat from the IRA had increased immensely. The numbers and quality of the Gaddafi guns essentially transformed the IRA from a standard terrorist organisation into a small army.
The arms importation was described as the greatest British intelligence lapse for many decades, since all the surveillance of the police, military intelligence, M15 and M16 had failed to uncover the Libyan connection.
It is now known that IRA leaders thought seriously of using the material to launch what they called a “Tet offensive.” This was a reference to the sudden Vietcong switch of tactics in the Vietnam war from guerrilla hit-and-run actions to fighting pitched battles.
The IRA considered whether the new Libyan arsenal made this a possibility. In they end they did not opt for open confrontation, but instead launched an intensified campaign using bombs, rockets and mortars against police and army barracks.
The IRA's thousand new Kalashnikov rifles gave it much more flexibility: pre-Libya, rifles were in short supply and attacks were cancelled rather than expose weapons to the risk of loss. But at a stroke the Libyan connection solved almost all the weaponry problems.
The organisation also used the Libyan guns to stage a violent new offensive both in Britain and on the continent, resulting in the daeths of a number of military personnel. The menace was such that the Ministry of Defence spent 126 million pounds on security measures at military bases in Britain and Germany.
The deadliest part of the Libyan consignments was Semtex plastic explosive, which was easy to conceal, more powerful and more penetrative than most other explosives and effective in very small quantities. The IRA employed it in boobytraps, grenades, rockets, mortars, and roadside bombs.
A British army general said privately: “The IRA's secret weapon isn't SAM-7 missiles. The thing that has made the single biggest difference to them is the Semtex - it's impossible to over-emphasise the flexibility it has given to them.”
Semtex was one of the mainstays of the renewed IRA campaign in Britain and on the continent. Three IRA members, shot dead by the SAS in Gibraltar in 1988, intended to set off a Semtex device during a changing of the guard ceremony there.
In 1990 a Semtex boobytrap bomb killed Ian Gow, the prominent Tory MP who was a close personal friend of Margaret Thatcher. A military source described how easily these could be attacked to a car: “The device is just a small box with a little magnet underneath it. It can be planted in a second by a guy bending over.”
Although off-duty troops, policemen and others at risk were regularly warned to check their vehicles, the devices nonetheless claimed many lives. In 1988 six soldiers, travelling in an unmarked van, were killed by a boobytrap in the Co Antrim town of Lisburn.
Two months later a Semtex device, concealed at the side of a road in Co Tyrone, was detonated as an unmarked coach was passing carrying several dozen soldiers back to their base after a leave in England. Eight of them were killed and 28 injured.
Security sources said the IRA showed particular ingenuity in adapting the Libyan weaponry to conditions in Northern Ireland, and combining military hardware with domestic material. One simple but highly effective device was the “coffee jar bomb.”
This, consisting of a small amount of Semtex inside an ordinary kitchen jar, could penetrate even heavily-armoured military vehicles. These and similar appliances, known as “improvised explosive devices” are now proving as dangerous in Afghanistan as in Northern Ireland.
Statistics give some idea of the effect of the Libyan armament. As it was brought into use the IRA killing rate rose from thirty-seven in 1986 to fifty-eight in 1987 and sixty-six the following year.
A small amount of the Libyan consignments is still hidden in Ireland. A year ago a small amount of Semtex was used in an unsuccessful rocket attack by dissident republicans on police. This is believed to have been filched from the mainstream IRA some years ago by those who broke away to form the so-called Real IRA.
The incident demonstrated that, more than two decades after it was smuggled into Ireland, some element of the Libyan consignments continues to pose a potential danger.