After the scare about “happy slapping” being filmed on mobile phones comes the panic about “happy decapitations” in Birmingham. Reports of an alleged plot to “behead a hero”, by kidnapping a British Muslim soldier and videoing his execution for the internet, have had a more explosive impact than another routine bomb plot.

We do not know the truth or otherwise of any allegations against individuals. But it would not be surprising if somebody had at least been fantasising about staging such a horrific stunt on video (no doubt others will be now). That sort of “reality terrorvision” allows the actors to project a powerful image that can make the illusory Islamist threat to our society seem all too real.

Home-grown terrorists aligned to al-Qaeda are not capable of bringing down civilisation. They are not fighting a war for state power. Their attacks are bloody PR events, their battleground the media. As Faisal Devji, author and lecturer, puts it: “Their acts function as exclamation marks.”

However, it is getting harder to pull off an exclamation mark-type bombing in Britain — and the fate of the 7/7 bombers showed that the price of success can be prohibitively high. So kidnapping a lone squaddie on leave and beheading him for a squalid video might seem a good idea to some: little effort, big impact.

After all, who needs big bomb plots when you can scare the life out of us with a cheap video on the web? They could look at the shudders caused by the British contractor Kenneth Bigley’s videoed execution in Iraq and imagine the publicity for a beheading filmed in Britain. Such films are intended to advertise in gruesome style the gap between terrorists and their enemies — that, as one statement infamously put it, they “love death, while you love only life”. Yet these images also feed off our own exhibitionist/voyeuristic video culture of happy-slapping/ Big Brother-style humiliation as entertainment.

For some disaffected Muslim youth drawn towards radical Islam, decapitation DVDs have become agit-porn; the murderer of the Dutch film-maker Theo van Gogh apparently spent his wedding night watching them with his bride. The rest of our world-weary society might think itself pretty unshockable, but the shock value of these videos is such that one foolish young Muslim was jailed for trying to impress a girl in Glasgow by showing her one on his mobile.

Little wonder if today’s wannabe celebrity terrorists were to ask themselves: is the internet video mightier than the bomb? Such is the level of anxiety now that it doesn’t even require a beheading plot to start the authorities acting like headless chickens — reports that somebody might have been thinking about it are enough to set them off.

But broadcasting our fears can only act as an invitation to any talentless fanatic to make a bid for stardom on “The Xecution factor” — coming soon to a mobile phone near you?

Times Recommends

• Navigating the new global archipelago
• Comment: McCain isn't Bush and voters know it
• Religion's history of self-inflicted pain