Sit down gently. Read Monday's list of "threats" facing modern Britain, and then read yesterday's list of how the coalition proposes to meet them. Next you should walk to the nearest wall and bang your head against it, hard, until you have counted to £45 billion.

The two lists simply do not match. The first so-called tier one threat is "attacks on cyberspace and cybercrime". The second is "international terrorism". The third is a foreign crisis "drawing in Britain", and the fourth is a natural hazard – "such as severe coastal flooding or an influenza pandemic". None of these constitute a military threat to the security of the realm.

Lesser threats are listed, including attacks from chemical, biological or radiological weapons, "organised crime" and "severe disruption to information … collected by satellites". Only in the lowest risk category, at number nine, do we encounter a "large-scale conventional military attack on Britain". This improbable event is put on a par with yet more terrorism, illegal immigration, and "disruption to fuel supplies or price instability", whatever the last may mean.

To none of the top threats is an army, navy or air force a sensible response. Almost all Britain's defence spending goes on threat number nine, a concerted attack on British soil, yet this is so unlikely these days, or in the foreseeable future, that it must merit some detailed assessment of balancing of risk against cost. It gets none.

The truth is that Britain's defence strategy has become a farrago of dogmas, traditions, maxims and cliches, most of them born of the second world war, the cold war and Tony Blair's fixation with fighting Muslims. Years of capitulating to the arms industry over glamour projects has now descended into this week's absurdities, the building of phantom aircraft carriers, continuing the "at sea" nuclear deterrent, and sending jets screaming over Britain's air space to shoot down 9/11-style terrorists. Even the Royal United Services Institute's Michael Clarke, defence lobby champion, admitted yesterday that the force structure was "slightly eccentric".

The security review's threat calibration is intellectually thin. It dares not ponder the implication of what is surely a fact, that Britain is less threatened now than ever in its history. Blair's quest for glory in allowing Britain to be "drawn into" seven foreign wars was just that, a quest for glory. The review offers no analysis of whether abandoning that quest might reduce other threats. It is like listing medieval diseases as "coughs, vapours, spots and lumps". The review is tough on insecurity, but un-tough on the causes of insecurity.

The chief threat is apparently from the flavour of the month, cyberspace, but it is hard to see how it is deterred by more ships and planes. Is the RAF going to target cyber-nerds with drones? As for terrorists, if anything has been learned from the last decade it is that "going to war" against them with main force glorifies them and serves their purpose. Nor is it clear how any threats are to be prevented by deploying pseudo-independent nuclear missiles. Do they stop Pakistan training al-Qaida bombers?

Policing and intelligence ensure that few terrorist acts occur in Britain; but even where they do, they destroy people and buildings. They do not endanger civil society and are anyway not susceptible to deterrence. The case for nuclear weapons is so weak that the chiefs of staff themselves recently pleaded for them to be removed from military consideration and treated as "political". The whole argument is puerile.

The bulk of the listed threats, such as natural disasters, swine flu, satellite interference or something called "price manipulation" should be of no concern to the armed forces. For the military establishment to exploit them to justify its existence is quite wrong, like invoking the brigade of guards to reinforce Asbos. These threats demand regulation, intelligence, policing and civil contingency. They do not need missiles or carriers.

The charge levelled at the defence review is that it is driven not by strategy but by money. In Britain there is no other way of conducting a defence review because special interests fight every inch of the way. The last substantive review was pushed through by John Nott in league with the Treasury in 1982. It was bold and was supported by Lady Thatcher, but the Falklands war scotched it, a war fought by the Royal Navy not to save the Falklands but to save the navy from Thatcher's cuts. Since then no defence secretary has had the guts to stand up to the defence lobby, and no prime minister has had the guts to support him if he did.

This defence review, in all its absurdity, was made unavoidable by the debt crisis but worsened by a sequence of weak Labour defence ministers and the indiscipline of the chiefs of staff. For the pundits to say the outcome is rushed is absurd. Britain spends millions on research, planning and strategy, in a myriad thinktanks and staff colleges. Their sole job is to think the unthinkable. If they never pondered what they might have to do if their grotesque gravy-train hit the buffers they should be sacked. As for Hillary Clinton's intervention, suggesting in effect that Britain take lessons in value for money from the Pentagon, it is laughable.

Only in the last three months have the defence chiefs been prepared to face the music, with some of them finally ridiculing the navy's carriers and Trident and the air force's strike fighters. By then the damage had been done and the procurement documents signed. This is not the coalition's defence review but Gordon Brown's, the outcome of the poison-pill contracts signed to protect jobs and make the coalition's job a nightmare.

None of the threats against which Britain's armed forces are deployed is on a par with those for which they were designed 70 years ago. They are second-order risks, requiring non-military agencies of government to counter. Were it not for Labour's foreign policy, subservient to American paranoia, there would be no need for most of the manpower and equipment now in use and planned. The defence establishment is a huge waste of national resources which, if the security review meant anything, could be mothballed against a rainy day.

Britain faces many challenges, including some involving violence, but the integrity of the state is not one of them. Those who argue otherwise should be seen for what they are, a chauvinist vested interest with money on the table.