Three years after targets in Saudi Arabia were hit by a series of suicide bomb attacks, the country has responded by investing heavily in anti-terrorist training, acquiring equipment and expertise from abroad, and a re-indoctrination campaign among suspected militants.

Beneath a baking sun in a dusty industrial estate outside Riyadh, Saudi Arabia’s anti-terrorist forces are being put through their paces over a daunting obstacle course while an officer casually fires live rounds over their heads and into the sand around their feet.

The paramilitary troops, wearing balaclavas and bulging with modern weaponry, certainly look the part. A couple abseil down a three-storey tower at alarming speed while a troop fitted out in black uniforms practice storming a building and capturing a potential terrorist.

The capital, which suffered the worst in the first of the al-Qaeda attacks, is now ringed with CCTV cameras, while police man permanent checkpoints at key intersections in the city. Major hotels are sealed off by concrete blast walls and foreign embassies are protected by troops in armoured cars.

"We had to start from scratch when we were attacked three years ago," said Colonel Abdulrahman Mogbal, the officer in charge of the main command centre in Riyadh. "We invested heavily in the latest surveillance technology from the West, particularly Britain and the US. We are now ready to face any threat."

As he spoke a bank of operators logged and processed calls to a 999 terrorist hotline, while officers monitored the busy rush-hour traffic through cameras located at key points in the city.

Colonel Mogbal, who has trained in Britain, said that the Saudis wanted to copy the Metropolitan Police surveillance system, which allowed the British authorities to track down last year’s suicide bombers in London. A similar security apparatus is now being installed in Riyadh with British help.

While foreign training, intelligence sharing and high-tech equipment can go some way to tackling the problem in Saudi Arabia, Western diplomats said that the real achievement has been the home-grown "hearts and minds" campaign which appears to have drained support for the militant cause.

General Mansour al-Turki, the spokesman at the Ministry of Interior, said that hundreds of suspected militants had gone through a re-indoctrination programme with spectacular results.

Called the "Counselling Programme", the project is aimed at combating the brain-washing that many young men have been subjected to by militant clerics or disciples of Osama bin Laden.

"This is a voluntary programme open to all prisoners. If they accept we work with them person to person with our team of psychiatrists and clerics. The aim is to persuade them that they are on the wrong path and need to return to society. We often involve their families. The clerics persuade them that this terrorist movement is not Islamic and talk them into changing their beliefs. More than 400 have been successfully treated and released back into society," he said.

In spite of the success of the programme, there are still real fears that further attacks will be made against vulnerable targets in the country.

Nawaf Obaid, the managing director of the Saudi National Security Assessment Project, said that four of the most wanted terrorist suspects in Saudi Arabia were still at large. He also warned of the dangers posed by the estimated 512 Saudi volunteers who went to fight in Iraq. Most are thought to have been killed, but some have become key figures in the insurgency and may one day return home.

The continuing dangers posed by al-Qaeda militants were highlighted in February after the failed suicide attack at Abqaiq, the world’s largest oil processing facility. Had the attackers succeeded in disrupting the flow of oil from Abqaiq it would have triggered a crisis on the world oil markets.

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