Declan Walsh writes:

If there was one telling moment in Pakistan in the 10 days since Osama bin Laden’s death, when a Hollywood-style American assault on a suburban house left the country reeling, torn between anger, shame and denial, it occurred late one evening on a prime-time television show hosted by Kamran Khan.

Chatshow hosts are the secular mullahs of modern Pakistan: fist-banging populists who preach to the nation over supper, often through a rightwing lens. Khan, a tubby 50-year-old journalist with neat glasses and a small chin, is the biggest of them. Every night on Geo, the largest channel, he rails against “corrupt” civilian politicians and America, and lionises the armed forces; some colleagues nickname him “the brigadier”. But as the country seethed over Bin Laden last week, Khan tore off his metaphorical stripes and stamped them into the ground.

The army had failed its people, he railed. To Pakistan’s shame US soldiers had invaded the country; their finding Bin Laden in Abbottabad, two hours north of Islamabad, was a disgrace. The country’s “two-faced” approach to extremism had disastrously backfired, he said, reeling off a list of atrocities – New York, Bali, London, Madrid – linked to Pakistan. “We have become the world’s biggest haven of terrorism,” he declared. “We need to change.” Viewers watched in astonishment. The unprecedented attack targeted not only the army chief, General Ashfaq Kayani, but also the most sensitive policies of the military’s premier spy agency, the Inter-Services Intelligence Directorate (ISI). Feared, reviled and admired in equal measure, the ISI is considered the embodiment of army power in Pakistan, the object of hushed deference. But now, as one US official told me, “the world has changed”. And the ISI finds itself in the line of fire.

The Bin Laden debacle has triggered a blizzard of uncomfortable questions, the sharpest come from Washington. How, President Barack Obama wondered aloud last Sunday, could Bin Laden shelter for years in a garrison town that is home to three regimental headquarters, the local version of Sandhurst, and thousands of soldiers? One retired US officer who has served in the region told me he had been mulling the same question. “All those times we drove up to Abbottabad, and we could have taken out our pistols and done the job ourselves,” he said. The CIA chief Leon Panetta, meanwhile, says he didn’t warn the ISI about the special forces raid because he feared word might leak to the al-Qaida leader. Behind the pointed statements lies an urgent question: was the ISI hiding Bin Laden?

The answer may lie inside the ISI’s headquarters in Abpara, on the edge of Islamabad. The entrance, beside a private hospital, is suitably discreet: no sign, just a plainclothes officer packing a pistol who direct visitors through a chicane of barriers, soldiers and sniffer dogs. But inside, past the smooth electric gates, lies a neatly tended cluster of adobe buildings separated by smooth lawns and tinkling fountains that resembles a well-funded private university. Cars purr up to the entrance of the central building, a modern structure with a round, echoing lobby. On the top floor sits the chief spy: the director general Ahmed Shuja Pasha, a grey-haired 59-year-old three-star general. One American counterpart describes him as “brilliant and extremely intelligent . . . Thoughtful, pensive and extremely well read; if he was in the US military he would be a very successful officer.”

Pasha and the ISI are the heart of Pakistan’s “establishment” – a nebulous web of generals, bureaucrats and hand-picked politicians (not always elected ones) who form the DNA of Pakistan’s defence and security policies. It has at least 10,000 employees (some say twice as many), mixing serving army officers, many on three-year rotations from other services, with thousands of civilian employees, from suited analysts to beefy street spies. In theory they answer to the prime minister; in reality they are a tool of the army chief, Kayani. To supporters, the ISI safeguards national security – monitoring phones, guarding the country’s nuclear weapons. But to its many critics, the ISI is the army’s dirty tricks department, accused of abduction and assassination, vote-rigging and torture, and running Islamist terrorist outfits. “The ISI,” said Minoo Bhandara, an outspoken Parsi businessman who ran a brewery across the road from army headquarters before he died in 2008, “is an institution full of intelligence but devoid of wisdom.”