LONDON — The discovery Sept. 23 of a huge cache of explosives and two heavy vehicles in a London suburb has confirmed that Irish Republican Army (IRA) terrorists have decided on trucks crammed with homemade "fertilizer bombs" as their most effective weapon.
The discovery of the weapons surprised many. British and Irish security experts, who forecast two weeks ago that a new Northern Ireland cease-fire was just around the corner, have been jolted into a profound reassessment of the IRA's strategy.
Announcing the find of 10 tons of explosives, Sir Paul Condon, London's police commissioner, said two trucks found at the same time had clearly been intended to carry out "significant and imminent attacks with the probability of grave loss of life."
The explosives, Sir Paul said, were of the type used in vehicle bombs in London's docklands and a shopping area in central Manchester earlier this year. At the site of the arms cache police shot dead one IRA terrorist suspect and arrested five others.
A nest of weapons
In addition to chemicals ready-mixed for use as bombs, police Sept. 23 found booby traps for placing under cars, several Kalashnikov assault rifles and hand guns, and two pounds of Semtex plastic explosive, which the IRA often uses to detonate so-called fertilizer bombs. Sir Paul and Prime Minister John Major both praised police and security forces for having found the bomb cache.
But British government ministers who had been hoping a cease-fire might soon be called admitted that the discovery suggested such hopes had been premature.
Sir John Wheeler, Britain's security minister in Northern Ireland, said the prospects of a new IRA cease-fire were not good. The IRA was "still ready to kill and attack.... If they are going to continue to conduct these operations against the United Kingdom and its citizens, then clearly they are not yet ready to embrace democracy," Sir John said.
While senior police officers and members of MI-5, Britain's security service, pondered the implications of the find, analysts said IRA units active on the British mainland had evidently decided truck bombs loaded with homemade explosive are their most potent terror weapon. The explosive was used in both the London docklands and Manchester attacks, two major economic targets.
Truck bombs were developed by the IRA about 20 years ago and used with deadly effect to mount assaults in Northern Ireland. Powdered fertilizer is mixed with ordinary household chemicals, and the resulting bomb is detonated by a small amount of plastic explosive attached to a timer.
The first truck bomb was used against the British mainland in 1992 when the IRA mounted an attack on the Baltic Exchange in the heart of London's financial district, causing $620 million in damage. Since then people entering the financial district have had to navigate their way through a "ring of steel" consisting of security barriers, closed-circuit TV cameras, and road closures on routes considered vulnerable to attack.
Police said the Sept. 23 find of explosives was enough for at least six bombs of the size used to blast Manchester's central shopping district on June 15.
British newspapers have speculated that planned IRA targets may have included the annual Labour and Conservative Party conferences in Blackpool (Labour) and Bournemouth (Conservative) due to be held in the next three weeks.
An IRA bomb planted at a hotel in Brighton during a Conservative Party conference in 1984 came close to killing the then Prime Minister Margaret Thatcher and seriously injured some of her Cabinet colleagues. Police said Sept. 24 that security arrangements for the Conservative and Labour conferences were being reviewed in the light of the bomb cache discovery.