Dissident republican terrorists in Northern Ireland used Semtex for the first time during an attack on police officers in County Fermanagh on Saturday.
One officer was hurt and another treated for shock after the device failed to leave an improvised rocket-propelled grenade launcher in the village of Lisnaskea.
It was the latest in a series of sporadic attacks, most the work of the Real IRA. Semtex, a military plastic explosive, has not previously figured in the organisation's armoury.
The substance proved a deadly weapon in the hands of the Provisional IRA during the latter part of its campaign, when it was used in a series of attacks that claimed many lives.
The initial assumption within the security forces is that republicans sympathetic to the Real IRA took Semtex stocks from the Provisional IRA before it put its weapons beyond use.
Deputy Chief Constable Paul Leighton said yesterday that the officers were lucky to be alive, but added: "For me it looks as if it came from old stocks. As far as I am aware it is the first time they have used Semtex."
Even small amounts of the Czech-made explosive, which reached the Provisional IRA in several shipments from General Gaddafi's Libyan regime, can cause considerable damage. It was estimated that two to three tons of Semtex reached Ireland, and the IRA proved adept in incorporating it into a series of home-made but deadly weapons.
These included armour-piercing grenades, mortars, under-car boobytrap devices and shoulder-fired rockets of the type used in Fermanagh at the weekend. It was the IRA's main weapon during bombing campaigns in England and was used in mortar attacks on Downing Street and Heathrow airport.
The two most active violent republican organisations, which sometimes work together, are the Continuity IRA and Real IRA, which planted the bomb which killed 29 people in Omagh in 1998.
Their activities have been disrupted by the PSNI, which regularly arrests known members. But although they are estimated to have fewer than a hundred activists, and only minimal support, they have never been eradicated.
All the signs were that the police had penetrated their ranks with agents and informers, but over the past year the sense has been growing that such infiltration has been limited.
A number of police officers have been injured during shooting attacks in recent months, with several of them lucky not to have been killed. This suggests that the groups have had some success in avoiding surveillance.
The police had already stepped up security precautions in recent times as the dissidents have repeatedly threatened to escalate their activities. The arrival of Semtex as a newly active component in their campaign means that a new review of security will have to take place.Reuse content