First, something good made in England: a film about America which I can recommend without reservation. Not only does this documentary betray no trace of anti-Americanism: it displays American values in a positive but unsentimental way that is rare to find in Hollywood.

“In the Shadow of the Moon,” directed by the Briton David Sington, tells the story of the Apollo missions in the words of many of the surviving astronauts — there is no narrative, just interviews interwoven with contemporary footage, accompanied by sensitive music.

Astonishingly, none of the images from outer space is computer-generated — and they are all the more beautiful for that. This handful of septuagenarians who once went to the Moon emerge as genuine heroes: not so much for their exploits, incredible though many now find them, as for the can-do idealism and philosophical serenity which they still radiate.

A remark that resonates today comes from Mike Collins, the Apollo 11 astronaut who had to stay in the command module and so did not join Neil Armstrong and Buzz Aldrin walking on the Moon. Speaking of Vietnam, he says that he still feels guilty about not serving there, even though comrades who did serve tell him that the space program was vital to sustaining morale. “That was my war,” he declares.

Looking back on our time in half a century, will those who do not serve in Iraq or Afghanistan or wherever else the jihad flares up feel a pang of conscience?

It would be nice to be the bearer of more good tidings from this side of the Atlantic, but the threats to our common civilization multiply faster than its defenders. This week Jonathan Evans, the new head of the British security service MI5, warned that the number of known individuals suspected of Islamist terrorism in Britain had risen to 2,000, an increase of 400 in a year. “We suspect there are as many again that we don’t know of,” he added. Besides these 4,000 jihadists, Al Qaeda has a much larger pool of sympathizers in the British Muslim community from which to recruit.

And the recruits are getting younger. Al Qaeda is now targeting teenagers as young as 15 through schools, mosques and the Internet. Three Muslims aged 16 or 17 are in custody, awaiting trial, and one 17-year-old, Abdul Patel, was sentenced recently.

These adolescents are quick, clever and emotionally immature: easy prey for the ghouls of Al Qaeda, who are now operating not only from Pakistan but an increasing number of Islamic failed states in East and North Africa. Only this week, a ring of some 20 jihadi recruiters, mostly North Africans, were arrested in Italy, France and Britain.

Such organized cells take years to unravel. But many of the “terrorist kids” have no connection with Al Qaeda, apart from an emotional commitment. They are “self-radicalizing,” according to an anonymous security official quoted in The Times of London yesterday. They don’t form cells, they don’t go to training camps and leave few traces. “With kids getting their ideas from the internet,” the official says, “there’s no way any security service can handle that without the help of the local [Muslim] communities.”

That help is precisely what has not, so far, been forthcoming. But when the novelist Martin Amis remarked that “the Muslim community will have to suffer until it gets its house in order,” he was howled down as a “British National Party thug” (i.e., a fascist) by his fellow professor at Manchester, the Guardian’s chief literary critic Terry Eagleton.

The suicide bombers have, of course, their own monstrous conception of heroism. The nature of its appeal to young, educated British Muslims was the subject of a two-part TV drama, “Britz,” shown last week on Channel Four. It was undeniably powerful, but it left me feeling very uncomfortable. The writer and director, Peter Kosminsky, tells the story of Sohail, a young British Muslim who works in counter-terrorism for MI5, and his sister Nasima, who becomes an Al Qaeda terrorist in protest against the security policy enforced by her brother.

In the final part, we see Nasima being trained in Pakistan, before returning to London to carry out her mission. Disguised as a pregnant woman, she calmly walks into an outdoor concert at the amphitheatre next to Canary Wharf tower and blows herself, her brother and hundreds of others to pieces. Her posthumous video tells her fellow Brits: “You are not innocent, OK?” Mr. Kosminsky explains what he thinks is the moral of his story: “British Muslims are infuriated by a foreign policy that appears to be an attack on Muslims worldwide — a new Crusade — and a shockingly large series of security measures which seem to be aimed solely at them.”

Real Al Qaeda terrorists don’t conform to this stereotype. Even if they did, it is monstrous to suggest that angry young men and women are justified in slaughtering their fellow citizens merely because they are “infuriated” by Islamist propaganda on the Internet — or sophisticated art house movies by directors like Mr. Kosminsky.

The war on terror will take a generation — at least — to win. It is time we started teaching our young people that this is their war, too. Do they, like the Apollo astronauts, know where their duty lies? Has anybody explained to them that it is their duty to denounce friends and relations involved in jihadi activities to the police? Above all, we need to reclaim the ideal of heroism from the jihadists. “In the Shadow of the Moon” should be compulsory viewing for the kind of Brits depicted in “Britz.”