MANSOUR Arbabsiar, the man at the centre of the alleged plot to assassinate the Saudi ambassador to Washington, has been described variously as ‘dishevelled’, ‘disorganised’, ‘unreliable’, and even ‘worthless’.

Hardly flattering labels, but not (yet) criminal offences. In any case, he hardly seems to be an Iranian version of James Bond.

Tom Hossein, an old friend of Arbabsiar’s, describes him as somebody “who was constantly losing his keys and cellphone”.

After a dismal 30-year career in which he failed in a succession of business ventures ranging from selling horses and cars to peddling ice cream and sandwiches, we are being asked to believe that he was entrusted with a complex assassination plot stretching from Tehran to Mexico to Washington.

And according to the American charge-sheet the Quds Force, an elite unit under the Iranian People’s Revolutionary Guards (IPRG), is behind this alleged attempt. So if this outfit commissioned a loser like Arbabsiar, it makes its leadership seem less like James Bond’s dreaded nemesis, SMERSH, and more like the Keystone Kops.

However, experts speak of the Quds Force with considerable respect. Mahen Abedin of London’s Centre for the Study of Terrorism, has this to say:

“Quds Force, although it’s a highly specialised department, is subject to strict, iron-clad military discipline. It is completely controlled by the military hierarchy of the IPRG, and the IPRG is very tightly controlled by the highest levels of the administration in Iran.” So much for the theory that the plot was being run by rogue elements within the Quds Force.

Abedin goes on to say: “It’s a very capable force – their people are very talented and they tend to be the best people in the IPRG.” And in 2007, the Los Angeles Times wrote that the Quds Force is considered by some analysts as “one of the best special forces units in the world”.

So hardly the kind of bumbling Clouseau-like amateurs they would have to be to recruit somebody like Arbabsiar. But wait, the plot gets even weirder: our hero flies to Mexico and makes contact with a member of the deadly Zetas drug cartel, and subcontracts the hit. Two wire transfers amounting to $100,000 are made from an unnamed source, and the price is set at $1.5 million.

To imagine that the Quds Force is unaware that large movements of funds are monitored closely is to seriously test our gullibility. And surprise, surprise, the Zeta contact turns out to be a US Drugs Enforcement Agency (DEA) agent. Now Al Quds (along with several million people who follow events in Mexico) must be aware that DEA agents are thick on the ground in a country infested with violent crime cartels that are smuggling drugs into the United States.

When Obama made the claim of Iranian involvement in the plot, I was reminded of the hapless Colin Powell, the US secretary of state, when he accused Iraq of having WMDs at the United Nations in 2003. He relied on bogus intelligence, and his unwitting collusion in that charade cost him his political career.

While I doubt Obama will be as badly damaged if and when the present accusations unravel, he will certainly end up with egg on his face. When I am presented with a criminal mystery of any kind, I apply the first principle of detection, and ask: “Qui gagne?”, or “Who gains?”

Random, unmotivated crime is relatively rare, and criminals – whether they are bank-robbers or suicide bombers – expect some reward, either in this world or the next. So how would the death of the Saudi ambassador to the United States benefit Iran?

Granted, there is little love lost between the ayatollahs and the Saudi royal family. But this Shia-Sunni conflict, combined with rivalry for regional supremacy, has been simmering for years without this kind of escalation. Ambassador Adel al-Jubeir has served as an interpreter for King Abdullah, and is reportedly close to him. But his death would hardly have decapitated the Saudi government.

Even Israel’s right-wing Jerusalem Post carries a word of caution: “But some outside experts, and at least some officials inside the government, remain wary, with some expressing concern that the administration of President Barack Obama is inflating the significance of a questionable plot to score political and diplomatic points against Tehran.”Theories about possible Iranian motives abound: according to one, Iran wanted to pay the US back for a number of covert CIA operations against it. In the recent past, three Iranian nuclear scientists have been assassinated, allegedly by Mossad, acting with American support.

Seymour Hersh, the well-informed investigative journalist, has written about covert operations deep inside Iran by US Special forces. And the crippling Stuxnet cyber attack on Iranian nuclear facilities was allegedly developed and carried out by Israeli and American experts.

In one Wikileaks cable, a senior Saudi diplomat was reported urging the United States to attack the Iranian nuclear programme and “cut the head off the snake”. So clearly, there are some grounds to believe that Iran could well consider a strike against both the USA and Saudi Arabia.

However, while the Iranians might have the motive and the means, it is the method that has caused eyebrows to be raised around the world. Such a complicated but crude plot carried so many risks of coming unstuck that it would take desperation or stupidity of a high order to set into motion. And as we have seen, Al Quds is anything but stupid.

Thus far, Iran’s ayatollahs have been cautious in the conduct of foreign policy. While they have used violent non-state players like Hezbollah in Lebanon and the Mahdi Army in Iraq to further its agenda, it has generally taken care not to risk outright confrontation with the US. In addition, its recent release of two American hikers accused of espionage would seem to indicate a desire to improve relations with Washington.

So who does gain from this bizarre episode? The US is already too preoccupied in the region to want to open another front.

Clearly, Israel is the biggest winner as the allegations isolate Iran still further and damage its international standing. I’m no conspiracy theorist, but if I had to bet, my money would be on Mossad.