Inch by inch and day by day, Britain seems to be sliding ever deeper into the shifting sands of the Malian desert. It is, in my view, a military adventure that's unnecessary, ill-advised and fraught with danger.

According to David Cameron, speaking in the House of Commons just 10 days ago, Britain now needs to show "iron resolve" to deal with a threat to our very existence from jihadi terrorists.

"We are in the midst of a generational struggle against an ideology which ... holds that mass murder and terror are not only acceptable but necessary," he told MPs. "We must... resist the ideologues' attempt to divide the world into a clash of civilisations."

And just in case you missed the Churchillian overtone, there was this: "We must demonstrate the same resolve and sense of purpose as previous generations have with the challenges that they faced."

So there you have it: we faced down Kaiser Wilhelm, Adolf Hitler, and Uncle Joe Stalin - and now, in the sands of the Sahara, we will not flinch as we confront, well, who exactly?

A few thousand fighters, many armed with weapons seized from Muammar Gaddafi's armouries in Libya, or purchased with cash obtained as ransoms for kidnapped Westerners, and as divided in their aims and their loyalties as their equivalents in Somalia or Afghanistan.

So why does Mr Cameron seem to be so convinced that the very survival of the Western world is at stake? Could it be that when gunmen over-ran that gas plant in the Algerian desert last month, someone put a briefing paper in one of his red boxes that seriously spooked him?

Perhaps it said something like this: "The best assessment of our security services is that there is now a real and growing threat from jihadi groups in Mali and elsewhere in the region that pose both direct and indirect risks to UK interests. Our strong recommendation is that we do not make the same mistake we made in Afghanistan, when we allowed the Taliban to take control of the country and offer sanctuary to al-Qaeda. That error, as you will be aware, led directly to the attacks of 9/11 and the deaths of 3,000 people."

Well, I'm sorry, but even if that's what the intelligence bods said (and of course, I have no access to their work), I don't buy it. In an impressively-argued piece in the Guardian this week, Jason Burke, one of the world's leading experts on al-Qaeda, wrote that, if anything, the jihadi groups are now weaker than they were a decade ago, and that they are "as far from posing an existential threat as they have ever been."

No one would argue, of course, that there is no threat at all. I have not the slightest doubt that even as you read these words, somewhere in Yemen, or Somalia, perhaps even in Mali, someone is planning another attack on a major Western target: a plane, or an oil refinery, or a transport hub.

But does the prime minister really think that by backing French military action, and by sending hundreds of British army instructors to train regional African forces, he is going to defeat the forces of evil, just as President Bush and Tony Blair thought they were doing in Afghanistan and Iraq?

Does anyone honestly believe that spending a couple of armour-plated hours in Algiers and Tripoli this week really changed anything, other than perhaps earning a few brownie points in Paris that might come in useful in future euro-rows? ("Now, François, remember how I supported you in north Africa, I'm sure you can help me out in Brussels ...")

Here's what I would do: leave president Hollande to get on with his own military adventure, trying as best he can to show that he's every bit as macho (it's the same word in French, apparently) as his predecessor, Nicolas Sarkozy, the Liberator of Libya.

Instead, send a senior Foreign Office (oh, all right, Mi6) envoy to talk to Tuareg leaders in northern Mali. Engage with them, get to know them, earn their trust, and mediate between them and what remains of the central government in the capital, Bamako, and the army.

Just maybe, we could persuade them that they're more likely to make progress towards a deal on autonomy by negotiating than by making common cause with the jihadi extremists who have brought them nothing except the (fleeting) attention of the world and thousands of rather well-trained French soldiers.

If that doesn't work, and if we're fans of the Danish TV political series Borgen, we could even seek the services of prime minister Birgitte Nyborg, who just last week did rather a good job stitching together a deal between the government and rebels in the fictional African state of Kharoun. (To my eyes, Kharoun bore a startling resemblance to Sudan, but I'm sure she'd manage just as well in Mali.)

By the way, if you've been worried about the fate of the priceless ancient Islamic manuscripts that were reported to have been destroyed in Timbuktu this week, it seems the early reports may have been unduly alarmist. The picture is still far from clear, but TIME magazine quoted a senior Presidential aide in Bamako as saying: "The documents... are safe, they were not burned. They were put in a very safe place. I can guarantee you. The manuscripts are in total security."

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