Hugh McManners: Blair has weakened our security by crying wolf

We cannot afford to suffer the attack that persuades us to take WMD seriously

The Government's attempts to trivialise their "45-minute" problem raise serious questions over whether they will be able to deal effectively with future attacks by terrorists or rogue states.

Tony Blair is not the only person to fail to realise that the 45 minutes applied only to Iraqi battlefield chemical and nuclear weapons and not to longer-range missiles. Had Andrew Gilligan's story about the doubts of intelligence officers included discussion of this caveat, the actual threat to the UK would have been very much clearer.

In the maths of intelligence evaluation: Threat to UK = Saddam's Intent x Saddam's Capability: 100 x zero = zero. The Risk to UK = Threat x Vulnerability: zero x zero = zero.

Had this true evaluation emerged at the time, Tony Blair's political ambition to help President Bush to topple Saddam Hussein would have been irretrievably damaged.

The only military significance of the 45-minute "fact" was for Mr Hoon; to ensure that every British service person who might come within range of Iraq's battlefield delivery systems had full chemical and biological protection kit, plus spares. The MoD did not do this.

MoD defence intelligence experts could tell you (if you asked) that 45 minutes was a figure from the Cold War, the time Soviet artillery took to get chemical or nuclear shells to the guns or mortar tubes, prepared and ready for firing. This presupposes that the ammunition was already close by the gun positions, and can only apply to battlefield rockets or missiles when they are in their actual firing positions, fully loaded and primed with WMD.

Because Iraq had significant amounts of Soviet equipment and had been trained by Russian officers, it could be reasonable to assume that the same 45-minute figure might be applied to their chemical or biological capability - all very conditional even before the Iraq Survey Group admitted defeat. There is in any event, no way, under any circumstances, that Saddam's forces could have achieved this speed of response.

But the significance of the 45-minutes issue today lies not in persuading the Prime Minister to follow his disingenuous media chief, Alastair Campbell, into retirement, but in the far more serious business of preparing the British people to face a real threat. Terrorists or rogue states are targeting British communities in places such as Cyprus and here at home. Intelligence experts agree that, sooner or later, one of the attacks being planned right now will succeed.

In Gulf War One, Iraqi Scud missiles, at the very limit of their range, hit Israel. Saddam was banking on an Israeli response, which he could claim as an attack by US-backed Zionists on Islam, uniting the Arab nation against the Allies. John Major scrambled the SAS en masse, and the regiment entered Iraq mob-handed in a desperate attempt to persuade Israel not to play into Saddam's hands by firing back.

This was not a careful, clandestine move to locate, fix and destroy Scud launchers, but a madcap race across the western desert using every "Pink Panther" available. The aim was to get willy-nilly into the launch area and create mayhem, to deter the Iraqi missile batteries from deploying. Israel would have been informed, and afterwards John Major broke security rules to tell the media. No launchers were actually destroyed. But, as it could not be explained at the time that the SAS action had an entirely political aim, this was irrelevant, and claims were made.

Another fact that Mr Blair ought to have known is that Scuds are not ICBMs, but Soviet battlefield delivery systems, designed to interdict deep into the enemy's rear areas, and deliver battlefield nuclear weapons. Post 1992, it was known that Saddam was developing new, improved-range Scuds, capable of hitting Jerusalem.Try telling the Knesset that the 45-minutes claim was an unimportant part of a vast body of so-called "evidence".

So in 1992, most of the SAS having been risked on a lethal wild goose chase deep inside Iraq, why in the build-up to the 2003 invasion, was there no diplomatic shuttling to keep a threatened Israel from getting its retaliation in early? Or indeed, as these missiles were said to be able to hit Cyprus, no evacuation of the British bases there? Answer: because it was known within intelligence circles that the 45-minute claim was nothing more than the most tenuous intelligence - which nobody actually believed.

The thought of a chemical or biological attack is so horrific that many people would prefer not to think of it at all. So how can the responsible authorities overcome such inertia and develop precautionary and emergency drills - particularly when wolf has been cried by the PM as part of persuading us to support a war opposed by so many electors, and by his own MPs?

We cannot afford to suffer the one serious attack that does persuade us all to take WMD seriously. Threat assessments need to be believed by everybody, so that the necessary legislation can be passed, money spent, and inconvenience suffered in order to be ready - both to deter attack, and to cope when eventually an attack gets through our defences.

We cannot afford to tolerate boys who cry wolf, be they journalists or prime ministers.

The author, a former British Special Forces officer, is a defence analyst