The huge damage caused ion the City of London, Manchester and other IRA bomb attacks could not have occurred without the type of home-made detonation cord which gardai discovered yesterday, writes Jim Cusack, Security Correspondent.
By JIM CUSACK
IN THE late 1980s, the IRA devised a method of increasing the explosive capacity of its bombs. This led directly to the destruction of hundreds of millions of pounds worth of commercial property.
After decades of experimentation, the IRA devised a means of using Semtex-filled tubing which was packed into sacks of standard home-made explosive (HME).
Bomb factories were set up throughout the Republic and in some nationalist areas of Northern Ireland.
In itself the HME was a relatively bulky and weak explosive. But when the Semtex tubing was placed in loops through the sacks of HME, it became much more powerful.
The tubing, known as improvised detonation cord, transformed the HME bombs into a force as powerful as if they were made from high-quality commercial explosive.
While the results were devastating, the source of the Semtex tubing was something of a mystery - as was its manufacture.
The gardai knew that a manufacturing operation was probably in place in this State and have been carrying out surveillance on several suspected bomb-makers for many months.
A figure known to have been involved in bomb-making in the past in the rough countryside on the Waterford-Kilkenny-Tipperary borders was eventually targeted as an important figure in the IRA bomb-making network.
This man is believed to have devised and overseen the system for inserting the highly malleable Semtex plastic explosive into the clear plastic surgical tubing used for intravenous drips in hospitals. Around 100 lengths of this tubing was intercepted by Garda special branch and officers from the Crime and Security branch in the midlands on Monday evening.
Immediately after, the Garda operation switched to Portlaw where further finds were made and arrests made.
The find is among the most important made by gardai.
Although only a relatively small amount of Semtex, probably a few kilos was involved, the importance of the discovery lies in the fact that the Garda operation probably prevented the IRA from launching another huge bomb or mortar attack.
After HME bombs, boosted by improvised detonation cord, were tested in the centre of Belfast in the early 1990s, the IRA shifted its attention to England in 1992. In two attacks in May and June that year some £200 million worth of damage was caused to the financial centre of the City of London by a bomb left outside the Baltic Exchange. The second bomb devastated retail and other property in west London.
Two years later the City of London was again attacked with another huge explosion near the NatWest Tower.
The bombs, weighing around two tons each, were the most powerful ever detonated by the IRA in Britain. Another similar bomb at Canary Wharf on February 8th last year marked the end of the 18-month IRA ceasefire. And another was detonated in the commercial centre of Manchester last June.
Similar types of explosive mixture had been used in landmine attacks in Northern Ireland since the late 1980s. One of the first was used to kill five British soldiers and a Derry man who was forced to drive a "human bomb" to the Border checkpoint on the Buncrana road, in late 1988.
About four years ago the IRA also introduced the same explosive charge into its large "barrackbuster" mortars which were used in attacks on security forces bases in Border areas between 1992 and 1994.
These "Mark 15" mortars contained up to 75 kilos of HME stuffed around the Semtex detonation cord. The mortars had a range of 70 to 120 metres and had sufficient force to kill within 300 metres from the point of explosion.
Several Mark 15 mortars were fired but relatively few deaths or injuries were caused, mainly as a result of good fortune.
One of the barrack-buster mortars was fired into the British army base at Osnabruck in Germany last June but it failed to explode.
If it had gone off it would probably have caused multiple deaths.