In 2006, Pakistan worked with the United States and Britain to crush a conspiracy to kill thousands of transatlantic passengers in terrorist attacks similar to 9/11, according to a new book authored by a former Central Intelligence Agency (CIA) analyst.

In his book, titled Disruption: Inside the Largest Counterterrorism Investigation in History, Aki Peritz claimed that the 2006 transatlantic aircraft conspiracy was “a plot to detonate liquid explosives carried on board airliners traveling from Britain to the US and Canada, disguised as soft drinks.”

British authorities learned details of the plot when they arrested two suspects on August 9, 2006, from the Walthamstow War Memorial in East London. This led to 24 more arrests across Britain and some more in Pakistan.

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The massive investigation, known as Operation OVERT, involved more than 800 surveillance officers in Britain. Across the Atlantic, the White House, CIA, the National Security Agency (NSA) and other US departments assisted the British in undoing the conspiracy.

“Cooperation from the US, as well as from Pakistan’s Inter-Services Intelligence (ISI), had been critical to the effort that ended with the raft of arrests on that August night,” Peritz wrote in an article published in Politico magazine this week that was adapted from his book.

British, US and Pakistani intelligence officials worked quietly for months “to crush what would come to be known as the transatlantic aircraft plot: a terrorist conspiracy to kill thousands of passengers by detonating liquid explosives hidden in plastic bottles,” Peritz added.

In Pakistan, authorities were looking for a British man from Birmingham named Rashid Rauf who apparently put the plotters in touch with Al Qaeda's leadership.

In Britain, authorities were alerted when one of the suspects, Abdulla Ahmed Ali, communicated with a man who had tried and failed to blow himself up on the Underground the year before.

“The British quickly informed the Americans that Ali was in contact with other suspicious individuals in Pakistan and Britain with known and suspected Al Qaeda ties,” Peritz wrote in the article.

Of 24 suspects arrested in and around London on the night of 9 August, 2006, nine men were tried, two were acquitted and seven found guilty of conspiracy charges.

“OVERT was, in many ways, the highwater point in the comity between the American and Pakistani intelligence services. The greatest level of cooperation occurred in the first years following 9/11,” Peritz said.

The author also acknowledged that after 9/11, “the two nations worked together to down many of the worst of the worst”. But added that “sometimes, they had to take pains to cover up the extent of this cooperation.”

One example of this secret cooperation, mentioned in the book, is that of a US drone strike that took out Al Qaeda external operations chief Hamza Rabia in 2005.

“It quickly became clear that Washington and Islamabad had worked together on the operation,” Peritz noted.

The operation that netted Rashid Rauf, the liquid bomber mastermind, was a similar model of cooperation.

On August 9, intelligence suggested Rauf was on the move in Pakistan. His phone was pinging off a series of cell towers. He was travelling fast on a highway — probably inside a vehicle, likely a bus, Peritz said.

“ISI officers had set up at a mobile checkpoint on a patch of earth where the highway intersected with some railway tracks. A CIA officer was on the ground, providing technical assistance. Rauf’s cellphone had been positively identified, and was headed right towards the checkpoint,” he said.

He pointed out that since several suspects involved in this conspiracy were British citizens trained in Pakistan and were planning attacks in the US, the intelligence agencies of all three countries had to get involved.

“London focused on the plotters, Washington monitored their emails, and Islamabad began to try to locate the mastermind hiding somewhere inside Pakistan," the former CIA analyst said.

Their cooperation led to Rashid Rauf’s arrest, who later escaped from custody in Pakistan, but was later killed. Some reports claim that he was killed by Pakistani authorities while escaping while other reports suggested that he was killed in a US drone attack in former Fata.

The author pointed out that the US and Pakistan had been conducting joint operations on Pakistani soil since mid-2002, although they did not always agree with each other on the nature of this cooperation.

“Pakistani intelligence officials certainly had their gripes about their American counterparts,” he wrote.

Talking about US concerns about Pakistan, he noted that America’s “Public Enemy Number One Osama bin Laden was lounging at his Abbottabad compound a little over two hours by car on the E-35 Expressway.”

Peritz added that during one meeting between the American and Pakistani spy chiefs around the time of the London arrests, then-ISI Director Gen Ashfaq Parvez Kayani muttered, “I’m tired of you Americans saying we are not doing enough to fight the terrorists.”

The Pakistanis, Peritz wrote, were irritated about being blamed for every slip-up that occurred and didn’t want to be left hanging if an operation on their turf went sideways.

“So, when Kayani asked CIA Director of Operations Jose Rodriguez, “Are you with me?” — was the agency behind the ISI in its counterterrorism operations? — Rodriguez told me he knew what answer was needed to keep the delicate relationship on track. 'Of course,' he replied," Peritz said.