This article was published in The Independent on 02/05/2011
John Gearson, reader in terrorism studies and director of the Centre for Defence Studies at King's College London, said organisations across the globe were now likely to "ramp up" their security.
"I think the significance of what has happened cannot really be overstated," he said.
"I would expect embassies and military bases around the world to be on high alert for some time.
"There will be concerns that there could be some sort of retaliation, that al-Qa’ida may well want to demonstrate that they are still strong and still in the game.
"The danger is that the Americans may well lose their focus, that they will relax and that will provide an opportunity for the remnants of al-Qa’ida to reform and grow stronger.
"Al-Qa’ida will remain a major security concern."
Former British Army colonel Richard Kemp, commander of British forces in Afghanistan in 2003, echoed his fears, suggesting the Taliban could now look to bin Laden's deputy, Ayman al Zawahiri, for leadership.
"I think this is not the end of al-Qa’ida by any means," he told the BBC.
"They will try and recover, they will undoubtedly try and strike back in some form. I don't suppose they will manage a major attack but they will try and strike back in some form in the short term, in retaliation for the death of bin Laden.
"And meanwhile, others will take on his mantle. Al Zawahiri, his number two, will presumably step up to lead al-Qa’ida now ... this is a major blow for al-Qa’ida and a lot of their supporters will now sit back and think."
Frank Faulkner, a senior lecturer in sociology and terrorism studies at the University of Derby, said revenge attacks in the aftermath of bin Laden's death were on the horizon, adding: "It's just a case of when and where."
"Every security operation in the world will be on the highest state of alert in readiness for any kind of attack by al-Qa’ida," he said.
"It is not going to come straightaway but al Qaida will want to show that it still has the capability to exact force against its perceived enemies.
"It is all about when and where.
"You can't possibly estimate how it will take place or where, but there will be some sort of situation arriving at some time."
While the Taliban's objective will be to hit back at the US, Britain will also be a "legitimate target" because of its close association with the superpower, he said.
But there is unlikely to be an immediate retaliation because al-Qa’ida will know that defences are being bolstered in the aftermath of bin Laden's death, making it "almost impossible" to launch a successful assault on the West, he said.
His warnings came as Americans celebrated their "victory" in Pakistan, which is expected to bring some form of closure for many of the victims of the September 11 terror attacks.
While Dr Gearson termed the development "a great day for Americans", Dr Faulkner urged caution.
"Just because you have decapitated the leadership of al-Qa’ida doesn't necessarily mean the organisation has been beaten because it obviously has not," he said.
"It is only part of the way towards eradicating the whole organisation - it is far from the end."
Professor Paul Wilkinson, chair of the Centre for the Study of Terrorism and Political Violence at the University of St Andrews, said the death of bin Laden would not spell the end of al-Qa’ida.
Asked about the possibility of al-Qa’ida carrying out a revenge attack, he told BBC Scotland: "I think it's highly likely, and I think President Obama was right to caution that there was likely to be an upsurge in terrorism as a result of the killing of bin Laden and certainly there shouldn't be any hasty winding down of the specialist services that counter terrorism in the international community. I think that would a great mistake.
"It's true that al-Qa’ida has suffered a huge setback in the Middle East because it's been effectively marginalised in the Arab awakening. People want democratic reform and freedom in the Middle East and, of course, democracy is the last thing that al Qaida want. They hate it, they regard it as a kind of western disease.
"Their real base of activity, the most important part of their activity, is in south and south west Asia and it would be a great mistake to think that that is going to stop any time soon. They are very deeply entrenched there, they are still recruiting large numbers of suicide bombers and they are still carrying out mass casualty attacks."
He added: "It would be very dangerous to assume that the death of Bin Laden means that journalists can write the obituary of al-Qa’ida."