The continued elusiveness of Osama bin Laden as he reached his 50th birthday on 10 March 2007 engendered much reflection among security officials about the condition and prospects of al-Qaida. The Pentagon chose to mark the moment with a diversion: the release of details of the interrogation of the group's operative Khalid Sheikh Mohammed. The fact that whatever importance he once had to al-Qaida must have been diminished by his incarceration since 2003, and by the evidence of al-Qaida's continued activities since then, was lost in most commentary (see "Al-Qaida's standing", 22 March 2007).

Landmark birthdays and leaked interrogation reports aside, any assessment of how well al-Qaida is doing today must take account of a range of factors: the growth of the movement in Iraq (where it has been recruiting more Iraqis rather than relying on paramilitary recruits from abroad), the pressures of conflict in the Pakistan-Afghanistan borderlands, and the impact of the damage (civilian casualties, detentions, rendition and prisoner abuse) of the "war on terror" launched by the United States after 11 September 2001.

A five-faced movement

In the aftermath of the 9/11 attacks, the Taliban regime in Afghanistan was rapidly terminated in a victory that was at the time presumed to be complete and definitive - so much so that the Bush administration could move over almost immediately to terminating the Saddam Hussein regime in Iraq. In practice, the original assessment was thoroughly misleading, on two counts.

The first is that Taliban militias systematically melted away in the face of formidable US airpower and a newly rearmed Northern Alliance. In one sense the militias were obviously defeated, but it was much more a matter of dispersal - moving back to towns and village, often with weapons and equipment intact. The second point is that many of the al-Qaida paramilitaries in Afghanistan also disappeared from sight; it is worth remembering the many occasions in which US troops deployed to al-Qaida training-camps only to find them deserted.

It is still valid to say that the al-Qaida movement was seriously affected by the events of October-November 2001. Some key leaders were killed and a few others, like Khalid Sheikh Mohammed himself, were captured. Many escaped to Pakistan, however, and indeed the very fact of the dispersal was instrumental in the gradual transformation of the whole movement. Al-Qaida had never been narrowly hierarchical, even before 9/11, though (especially when there were secure bases in Afghanistan after the Taliban takeover in 1996) there was a degree of central organisation. What has happened since 2002, though, is that a new generation of middle-ranking leaders and organisers has emerged (see Jason Burke, "Al-Qaeda: the second coming", Observer, 11 March 2007).

Some members of this new generation are known to western agencies but many are not. One who has been identified is an Egyptian national, Abu Ubaidah al-Masri; he was previously thought to have been involved in operations in Afghanistan but is now believed to direct specific operations from western Pakistan, including the plan to attack transatlantic air routes out of London in summer 2006 (see Mark Mazzetti, "New leaders direct Qaeda resurgence", International Herald Tribune, 3 April 2007). Others have not been identified, but it is believed that responsibility for operations is shared by a number of people. They may have collectively replaced Khalid Sheikh Mohammed, although there remains some doubt that he was ever as significant as the Pentagon claims.

More generally, a picture is now emerging of the al-Qaida movement as having five main components. The first is the original leadership of Osama bin Laden and his deputy Ayman al-Zawahiri; the former is primarily more of a figurehead, while the latter is (as he has been for a long time) important in its strategic planning.

The second is a fairly strong concentration of activity in northwestern Pakistan, including training-camps. This activity maintains informal links with the third element, a series of "hubs" in other countries where a dispersed local leadership retains links with the core group that is centred largely in Pakistan. Such hubs may be small, they may communicate largely through personal contact and the use of messengers, and they may have quite loose connections with groups in their own countries. A number of them (such as the separatists in southern Thailand) have their own agendas, and may work almost entirely on their own while embracing some of the long-term aims of the movement.

The fourth component is a major theatre of armed activity in the form of the al-Qaida movement in Iraq. This is proving to be one of the movement's most valuable assets, and its value is if anything strengthened by its large measure of autonomy from anything happening in Pakistan. Robert Richer, an associate director of CIA operations in 2004-05, says: "The jihadis returning from Iraq are far more capable than the mujahideen who fought the Soviets ever were. They have been fighting the best military in the world, with the best technology and tactics."

The fifth component of the new al-Qaida, which encompasses all the above, is a more general base of support which stretches across Muslim communities in many parts of the world. This has been highlighted by recent developments in the Maghreb (Morocco, Algeria and Tunisia) and, especially, the Horn of Africa. In the wake of its intervention in Somalia since December 2006, the Ethiopian government is reported to have detained people from several countries and allowed US officials into its prisons to question them (see Anthony Mitchell, "U.S. interrogating terror suspects in Ethiopian prisons", International Herald Tribune, 4 April 2007).

This is but a small part of the assimilation of Somalia's domestic conflict into the war on terror's global framing. The United States's broader response on the continent has been to set up the new Africa Command, along the lines of Central Command (Centcom), responsible for military operations in recent years from Somalia through the middle east and south Asia to Pakistan (see "The United States and Africa: eyes on the prize", 15 March 2007). This scale of response in its own way is acknowledgment of al-Qaida's reinvention.