The Republic is Europe's 'weakest link' in security and defence preparedness terms, writes Tom Clonan
A key feature of the September 11th attacks in the US was the breach of cockpit security by armed terrorists on board commercial passenger jets. Once inside the cockpit, the terrorists - who had availed of pilot training - were able to take the controls of various hijacked aircraft and direct them at the Twin Towers and other targets. Immediately after these attacks, airline safety and counter-terror measures focused on cockpit security.
Reinforced doors separating the flight crew from the passenger cabin were introduced along with more stringent searches of passengers for offensive weapons such as knives or other sharp objects which could be used to disable or kill airline cabin crew.
In the US, the number of armed air marshals was increased to deal with potential terror attacks involving attempts to take control of an aircraft in flight.
Faced with these challenges, terrorist groups such as al-Qaeda will have had to reconsider their strategy of seizing control of commercial aircraft. Yesterday's foiled attacks in Britain suggest that such terrorist groups - particularly those with a propensity for suicide attacks - have shifted their focus from gaining control of passenger aircraft to destroying them in mid-flight.
Security sources in Britain and Ireland have informed The Irish Times that a liquid explosive appears to have been intended for use against a number of passenger jets leaving UK airports and bound for the US.
These sources indicate that the type of liquid explosive intended for use did not consist of standard military or commercial high-explosives such as TNT, Semtex, C4 (plastic explosive), RDX (research development explosive) or their derivatives. Nor is it believed that the suspected terrorist cell had commercially or militarily produced high explosive gel or liquid explosive variants.
Rather, initial indications are that the liquid explosives intended for use in the foiled attacks consisted of a "home-made" variety of chemicals, including nitrogen, acetone and peroxide. The DIY liquid explosives in question - which feature in al-Qaeda training manuals - are believed to consist of tri-acetone-tri-peroxide (TATP) or nitroglycerine-type mixtures.
These liquid explosive cocktails could be easily concocted by someone with a rudimentary knowledge of chemistry - with readily available over-the-counter chemicals and products. Despite their simple formulation, however, TATP and nitroglycerine liquid explosives - derived from white crystalline powders and milky in colour, consistency and appearance - are highly explosive and lethal.
On detonation within the pressurised cabin of a commercial passenger jet, a TATP or nitroglycerine mixture would raise the internal temperature to over 1,000 degrees centigrade. The detonated device would also generate a powerful shock-wave through the passenger cabin.
The combined effects of such an explosion would instantly incinerate an aircraft's internal fittings along with its passengers and crew while deflagrating the plane - igniting the aircraft's fuel tanks - and subjecting it to traumatic decompression, rupture and complete structural failure. If such a device was detonated in mid-flight on board a US-bound Continental, American Airlines or US Airways jet over the Atlantic, there would be no survivors.
If such a device was detonated on board such a plane as it made its low-level final approach to land at a US airport - most likely over a densely-populated urban area - the death toll would be higher, with many fatalities on the ground.
In yesterday's operation to foil a possible imminent attack on a number of US aircraft, all initial indicators point to a terrorist cell with a remarkably similar modus operandi to that of the July 7th London Underground bombers. In both instances it would appear to be the case that a relatively large number of young British Muslims - using home-made explosives and apparently acting in a co-ordinated fashion - planned to mount suicide attacks on mass public transportation systems at peak travelling times in order to inflict the maximum number of civilian casualties.
If verified in the coming days and weeks, such a planned attack carries with it the hallmarks of a classic al-Qaeda-inspired operation - seeking to perpetrate a mass-casualty incident on "soft" civilian targets.
The target of yesterday's foiled attacks would appear to have been US aircraft, US citizens and possibly their destinations in America, including the cities of Los Angeles, Boston and New York.
Terrorist groups such as al-Qaeda would cite America as its number one enemy and its highest-priority target. Britain, Ireland's closest neighbour, has been ranked by the international intelligence community as being a close second to the US as a preferred target for terror groups such as al-Qaeda. Indeed, a number of senior British police commissioners along with prime minister Tony Blair have stated that terror attacks on Britain by such groups are inevitable.
Ireland, by virtue of its proximity to Britain and by virtue of its porous land, sea and air borders, would be considered by many terrorist groups to be an ideal staging post for attacks on the UK.
Unlike many of our EU partners, Ireland does not invest enough resources in police and military security and intelligence infrastructure. This may be a by-product of our long-held "neutral" status and may derive from a naive belief in our "invulnerability" from foreign attack as an island nation.
Ireland would be considered by many - both within the international security and intelligence community as well as among international terrorist organisations - as Europe's "weakest link" in terms of security and defence preparedness.
As groups such as al-Qaeda continue to evolve new terror strategies to strike at the US and Britain, it is inevitable that at some point Ireland will share in the consequences of such an attack - either directly or indirectly. In terms of an attack by a group such as al-Qaeda on vital infrastructure - such as nuclear power plants - in Britain, Ireland's emergency response capability is woefully inadequate.
In terms of a direct attack on British cities or urban areas - launched, for example, by way of passenger jets - yesterday's events should give the Irish authorities much to think about. As terrorists evolve new and ever more ingenious and diabolical ways to smuggle high explosives on to passenger aircraft, the Irish airline industry and our airport authorities ought to consider such threats in the context of our proximity to Britain.
Already considered to be "Europe's weakest link" in terms of security awareness and infrastructure, Ireland's ports and airports may well have already been identified as ideal launching points for future attacks on Britain.
• Dr Tom Clonan is a security analyst. He lectures in the School of Media at the Dublin Institute of Technology.