It is a sight the world had got used to: a crater in the road where the suicide bomber detonated the explosives packed into his vehicle; the pools of blood and hunks of flesh of people caught in the blast; ruined buildings where floors have collapsed on top of each other; shocked survivors wandering amid the mangled cars and broken glass.

Almost invariably over the last decade such carnage has been the work of al-Qa'ida or similar Islamic fundamentalist movements such as the Afghan or Pakistan Taliban. But the latest such explosions, coming a year after the killing of Osama bin Laden, took place this week in the Syrian city of Idlib where two suicide bombers blew themselves up outside the headquarters of army and airforce intelligence services. The Syrian government says that nine people were killed and 100 wounded.

The Syrian opposition claimed that these and other attacks on symbols of the Syrian state are the work of the Syrian government seeking to discredit protesters. They said they were "fabricated, staged explosions". But the attacks have all the hallmarks of an al-Qa'ida operation and the CIA has confirmed that previous suicide bombings in Syria have been the work of al-Qa'ida. An al-Qa'ida inspired group called the al-Nusra Front to Protect the Levant has claimed a bomb in Damascus that killed 10 people last week.

These bombings are significant because they show that al-Qa'ida is still very much in business, despite the death of Bin Laden and other al-Qa'ida leaders. It not only still exists but it is becoming engaged in new conflicts that have followed the Arab Spring. Al-Qa'ida has always been the child of war. This was true in Afghanistan when the Taliban were fighting to take over the country prior to 2001; in Iraq after the US invasion in 2003; and in Yemen where civil conflict has escalated since the Arab Spring last year.

Al-Qa'ida-type Sunni fundamentalist groups flourish in times of conflict because holy war is at the heart of their faith and martyrdom opens the way to heaven. Its militants make good soldiers. A moderate Sunni in Baghdad told me towards the end of the sectarian civil war there in 2007 that al-Qa'ida fighters would only be allowed back into his district if it came under assault from Shia militiamen. Otherwise, they were hated and feared by local Sunni for their ferocity, fanaticism and violence. "Why would you let them back in then?" I asked. "Because they will fight to the death," he explained.

It may be comforting for Western governments to imagine that the jihadist version of Islamic fundamentalism is a back number since the onset of the Arab Spring. There are now other avenues for effective protest by disaffected Muslim youth. But this view is deceptive because, if the Arab Spring has brought change, it is also brought armed conflict to much of the Arab world where change has been blocked, as in Syria, or state power has weakened, as in Libya.

Developments in Syria are important because al-Qa'ida is beginning to show strength in a core region of the Middle East and is no longer confined to isolated fastnesses in north-west Pakistan, Yemen or Somalia. The convulsions of the Arab Spring may have been inspired by different ideas than those of Bin Laden and his followers, but the weakening of police states across the region makes it easier for al-Qa'ida to operate. The Arab world today looks more and more like it did in the 1950s and 1960s, when nationalists, Islamists, Communists, secularists and liberals contended for power. After the uprisings of last year many countries will be freer, but many will also be more divided and violent.

How did al-Qa'ida survived the intense pressure placed on it by security services after 9/11 and will it be able to do so in future? The answer is that it did so because the organisation never existed in the form that so-called counter-terrorism experts imagined. It was never a sort of Islamic Comintern, with tentacles stretching from Waziristan to Birmingham. When it was at its strongest as a cohesive group at the time of 9/11, Bin Laden could only look to some 100 men to facilitate the sort of attacks he intended. On the other hand, the ideology he espoused and the fundamentalist jihadist tendency in Islam, is far broader and far more difficult to eliminate.

Groups that have no organisational connection with al-Qa'ida now employ its tactics because they are effective. As in Idlib a couple of days ago this involves what anarchists used to call "the propaganda of the deed", the destruction of a highly visible symbol of the community or state under attack. Suicide bombing in which the perpetrator knows he is going to die has the tactical advantage of enabling untrained but fanatical recruits to inflict maximum damage. But for al-Qa'ida bombers self-immolation is much more than this, serving as a demonstration of their faith.

Al-Qa'ida-type organisations may find the political waters of the Middle East easier to swim in in future because they can take advantage of a series of escalating conflicts. Bin Laden saw his enemies as being primarily American, but, from the beginning, al-Qa'ida's franchisees have had different priorities. The Arab Spring was a popular uprising against police states in Tunisia, Libya and Egypt but it was not only that. East of Egypt it fed into, and exacerbated, the conflict between Shia and Sunni in Syria, Bahrain and Iraq. It has deepened the confrontation between the Iranian-led coalition, broadly opposed to US influence in the Middle East, and its Saudi-led opponents.

Western governments and media give the impression that al-Qa'ida and its associates are purely anti-Western organisations. The counter-terrorism industry, often peopled by academic, journalistic and intelligence mountebanks, ignores or downplays the degree to which jihadist militants target Shia civilians more frequently than Westerners. In Pakistan, particularly when atrocities occur in the tribal areas of the north-west, this slaughter is scarcely mentioned in the papers or on television. Likewise in Iraq, the butchery of Shia civilians remains so much the norm that it is infrequently reported.

The Sunni-Shia conflict is getting hotter, fuelled by the ongoing confrontation between the Shia majority in Bahrain and the Sunni al-Khalifa monarchy. There are signs of greater sectarian tension in Kuwait where the Shia are a minority. The core of the regime in Syria are the Alawites, a sect related to Shi'ism ideologically, but its pro-Shia identity is reinforced by its political alliance with Iran and Hezbollah in Lebanon. As the mood in Sunni states becomes more anti-Shia this will benefit Sunni fundamentalist groups like al-Qa'ida that have always denounced the Shia as heretics and as worthy of death as Western infidels. Al-Qa'ida frequently targets Shia shrines in Iraq, but when the Saudi-backed Bahraini government crushed protests in March last year they demolished some 30 Shia mosques and meeting places. Even the graves of long dead Shia holy men were destroyed.

There has always been a contradiction in the US-led war against al-Qa'ida and the Taliban. It has been conducted in alliance with two states – Saudi Arabia and Pakistan – whose policies are geared to supporting Sunni fundamentalist movements. The ISI military intelligence service in Pakistan was central to the birth of the Taliban and their resurgence since 2006. The Pakistani military has been successful in being, at one and the same time, America's ally against al-Qa'ida but also suspiciously incapable of wiping it out entirely. To do so would devalue the ISI's co-operation in the eyes of the US.

The relationship of Saudi Arabia with al-Qa'ida is a little different. Saudi security pursues its militants, but Wahhabism, Saudi Arabia's variant of Islam, is very close in ideology to al-Qa'ida. It is a fundamentalist faith, its original adherents committed to restoring primitive Islam, fighting to the death and entering paradise as martyrs. It is fiercely anti-Shia, whom it sees as being on the offensive since the Iranian revolution in 1979.

Saudi Arabia and Qatar are of crucial importance for the future of Sunni fundamentalism, whether it is under the rubric of al-Qa'ida or some other like-minded organisation. The balance of power in the Arab world has changed, with states such as Egypt, Syria and Iraq weakened or in turmoil, and the Saudis and Qataris filling the leadership vacuum. This strengthens Sunni fundamentalism, of which al-Qa'ida is but one extreme offshoot. Bin Laden may be dead, but Islamic radicalism – and the causes which gave rise to it – is very much alive.

German investigators find 'treasure-trove' of intel

German investigators discovered information about al-Qa'ida's plans to seize cruise liners and wreak havoc in Europe on a memory chip containing a pornographic video that was found in the underpants of a 22-year-old Austrian terrorist suspect.

Details of the potentially devastating al-Qa'ida plot were released yesterday by the television network CNN to coincide with the first anniversary today of the assassination of Osama bin Laden in Pakistan.

CNN said German investigators managed to unearth what was described as a "treasure-trove" of intelligence about al-Qa'ida's plans. It included a plot to hijack cruise ships and dress captured passengers in Guantanamo Bay-style orange uniforms. Al-Qa'ida planned to film the execution of the captured passengers "one by one" if the authorities refused to comply with its demands. The information also included details about al-Qa'ida's plans for gun attacks in Europe.

German intelligence officials were said to have unearthed the information while interrogating a 22-year-old Austrian citizen, Maqsood Lodin, who was on a counter-terrorism watch list when he was pulled in for questioning in Germany in May last year. Mr Lodin and a suspect named Yusuf Ocak are on trial in Berlin, where they are pleading not guilty to terrorism charges. Prosecutors believe the pair met at an al-Qa'ida terrorist-training camp in Pakistan and were sent back to Europe to recruit a network of suicide bombers.

The device found in Mr Lodin's underwear contained a pornographic video called "Kick Ass" and a file marked "Sexy Tanja". German investigators were said to have taken weeks to crack a password and software contained in the video which finally revealed the existence of more than 100 al-Qa'ida documents concealed inside. Intelligence officials said they believed that although the plans had been conceived in 2009, they remained the template of al-Qa'ida's future strategy.

On Monday, Mitt Romney, the presumptive Republican nominee, dismissed suggestions that faced with a similar choice as President, he would not have ordered the military to kill the al-Qa'ida leader. Asked whether he would have given the order to go after Bin Laden, Mr Romney insisted in a reference to the former US President renowned for his reluctance to use military force: "Of course. Even Jimmy Carter would have given that order."