IN case you missed it, since Monday an “Irish-related” attack on Britain has been “a strong possibility”. At the same time, an Al Qaeda attack is “highly likely” and “only a matter of time”.

This presumably means one will occur — though, since August 2006, when this alarmist language was first to put us on continuous alert, terrorism has been like mad flu disease, afflicting the civil service but strangely absent from the nation at large.

I hesitate to tempt fate, but this dog's dinner of nouns and qualifiers cannot mean anything to the general public. Rather than describing a menace to the British state, the words are more a comment on English teaching in schools. They are verbal garbage, reflecting a habit of bureaucratic mind and relieving public services — airport security, railway guards, traffic police — of the need for courtesy. They just want to keep the public scared and paying taxes.

Travelling on a First Great Western train nowadays is like entering Guantanamo — a cacophony of repetitive announcements telling passengers to protect their belongings at all times and inform the police if they see anything suspicious. Likewise the fatuous frisking of old ladies at airports, the half-hearted searching of bags in shops, the reams of safety literature pouring from the nation's printers. It is the white noise of state fear.

Nothing is as absurd as home office (interior ministry) “threat levels”. They purport to grade the risk of something called an “attack”. This is not defined, but graces a crime with the glamour of a soldierly act. It grants terrorism political status and thus dusts the security industry with the glory of defending the realm.

Above all the threat must be kept alive, sorted into classes of low, moderate, substantial, severe and critical. We are currently at severe. What regius professor of English chose these words? I would put 'severe' below 'substantial', the word being a strengthener of very, while 'substantial' has substance. But I assume the civil service has done focus groups and sweat tests. 'Substantial' was perhaps greeted with a shrug, while 'severe' brought on the shakes. As for critical — Mujahideen “expected imminently” to hurl bombs down Oxford Street — it is surely the most devalued word in the dictionary.

There is no way a member of the public can sensibly use the information that an Al Qaeda threat has altered from substantial to severe. These are abstractions. Are we supposed to calibrate our dread with home affairs minister Theresa May each morning, treating all dark skin as suspicious and every beard as hiding a foe?

The former home affairs minister, Alan Johnson, raised the Al Qaeda threat level in January from substantial to severe, yet added that it would be “pretty daft” to say why. Under his predecessor the security service boasted that it had tabs on 2,000 individual terrorists, 200 networks and 30 active plots. The impression was the more the merrier.

There is now an extensive police and industrial lobby in Britain dependent for its resources on maintaining a high level of public fear. The lobby thrives on its own failures. The incidents in America on 9/11 (2001) and in London on 7/7 (2005) saw the greatest ever peacetime growth in spending on security. Unlike most forms of public spending, this one could by its nature demand cash with menaces and with no account of value for money.

The fear must be sustained if the resources are to flow. The West has been starkly free of terrorist “attacks” over the past decade. The lobby may plead this proves the money was well spent, but the staggering cost of anti-terrorism since 9/11, including two foreign wars, must have surpassed all actuarial calculation of western lives saved thereby. —The Guardian, London