When the Taliban broke more than 750 prisoners out of jail this summer, in one of the most spectacular attacks in living memory, Nato's response was instant but invisible.
Senior commanders scrambled every drone they could spare as prisoners poured out of Kandahar jail.
The closest Nato garrison had hunkered down inside their base, afraid of more attacks, as prisoners poured into the night.
But commanders at nearby Kandahar Airfield watched live pictures of the anarchy, from the comfort of their operations room, as wave after wave of escapees began marching east, to sanctuaries in Pakistan.
A fleet of Predator drones criss-crossed the skies some 35,000 feet above Afghanistan's second city, flying throughout the night and long into the next morning, as rag-tag columns of men made good their escape.
Some of the prisoners went straight to Arghandab, just outside the city, where they fought with Nato troops a few days later. But most of the 400 Taliban, who were among the 750 inmates freed, fled back to Pakistan - beyond the reach of Nato's force. Or so they thought.
International troops are using drones to patrol Pakistani airspace in a bid to monitor insurgents on both sides of the border.
"We wanted to see where the prisoners went," said one official in Kabul, hinting that the fugitives had betrayed their hideouts when they fled.
It is an open secret that armed Predator drones, operated by the CIA, are flying routine fire missions inside Pakistan against Al Qa'ida leaders.
Islamabad insists it will never sanction American soldiers on its soil, but senior Nato officials insist the drones are there with tacit, if sometimes strained, consent of Pakistani officials.
The most notable example of a drone attack came last January, when a missile from a Predator hit a terrorist safe house in Waziristan, killing Abu Laith al-Libi, the man accused of plotting an attack against Bagram airbase, when US vice president Dick Cheney was visiting. That attack,in the Pakistani tribal region of Bajaur, targeted and missed al-Qaida's number two leader, Ayman al-Zawahri.
At the end of last month, a drone operating in northwestern Pakistan pinpointed al Qa'ida's chemical engineer, Abu Khabab al-Masri, who was a key figure in the group's production of chemical weapons and conventional explosives. Al Qa'ida has confirmed the death of the operative who was killed by a missile, along with five other people. He had earlier been reported as having been killed in the attack last January and had a $5m reward on his head.
Nato sources continually blame Pakistan for a surge in Afghan violence this year, and growing frustration at Pakistan's failure to tackle the Taliban on their side of the border has prompted talk of Nato operations against the insurgents on both sides of the Durrand line.
"The CIA already conducts operations in partnership with the Pakistanis," said a senior Nato official in Kabul. "Nato would like to have the same relationship with Pakistan."
The drones watch and log the movements of senior Taliban commanders in Pakistan's lawless tribal areas. Unlike the presence of special forces, they carry far less political risk.
Most of them are flown from an airbase in America, and if they crash - which has happened - they don't create "friendly" body bags.
The Taliban claim they can hear the tell tale buzz of unmanned aerial vehicles, of UAVs, before an attack. But most of the time they circle too high to be beard or seen, beaming back images of whatever's going on below. They only swoop lower when they want to fire, or take a closer look.
The army call drones their "unblinking eye," and they rely on them for almost all their major operations. One senior airborne officer told The Independent there was no doubt the aircraft had saved British lives.
"They are so good," he said, "they are the first thing we ask for when we plan an operation.
"The big thing is that they help us at the lowest tactical level. They find information, that which allows us to make decisions."
Moments before soldiers storm compounds or search houses, drones relay messages to their commanders warning them how many fighters to expect, and what weapons they have.
On a search operation in Helmand, against a suspected bomb factory, drones directed troops to return to a compound they had already searched, after it spotted bodies hiding in a nearby treeline.
Smaller versions of the predator are flown from Kandahar and Camp Bastion. The British hired a model plane enthusiast to help them take off and land, while even smaller drones - the size of remote controlled toy planes - are flown by artillery troops from the forward operating bases scattered across the provinces.
But the information is not always fool proof. America is once again investigating claims its warplanes killed 89 civilians in an airstrike in Herat last week. The Afghan president, Hamid Karzai, has fired two senior Afghan officers for their role in the attack.
There's little doubt the US Special Forces who called in the airstrike were relying, in part, on information from a drone that was watching the Taliban commander they were hoping to arrest.
It's just possible that the "thorough battle damage assessment" that American officials said proved that they had only killed insurgents was also done by a drone. President Hamid Karzai disagrees, and the Americans have, reluctantly, launched an investigation.
Perhaps more telling, is that three months after the great jail break, not one of the fugitive prisoners has been arrested.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies