Inside the IRA arsenal

Intelligence sources in Britain and the Irish Republic estimate that there are just 40 people actively involved in executing IRA operations, and perhaps 400 overall. Most of their arms are stored in the Irish Republic, but small stocks are held in Northern Ireland.

Large consignments came from Libya and Czechoslovakia, but more recently most attempted deliveries have come from the US, although most were foiled by the FBI and US Customs.

The IRA is estimated to have enough small arms, machine guns and ammunition to equip the equivalent of two British army battalions and to sustain its guerrilla war indefinitely. In addition to the arms listed in the table, the IRA relies primarily on home-made explosives - Anfo (ammonium nitrate and fuel oil) and Coop (weedkiller and sugar).

These explosives are highly effective, but need a high explosive like the Czech-made plastic explosive Semtex to set them off.