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 plane 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 35,000ft above Afghanistan's second city, flying through 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 prisoners, 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 an attempt 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 Qaeda 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 Qaeda's number two leader, Ayman al-Zawahri.

At the end of last month, a drone operating in north-western Pakistan pinpointed Al Qaeda's chemical engineer, Abu Khabab al-Masri, who was a central figure in the group's production of chemical weapons and conventional explosives.

Al Qaeda has confirmed the death of the operative who was killed by a missile, along with five other people. “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. The Taliban claims that it can hear the tell-tale buzz of unmanned aerial vehicles, or UAVs, before they attack. The army describes drones as its “unblinking eye,” and they rely on them for almost all of their major operations. One senior airborne officer said there was no doubt the aircraft had saved British lives. “The big thing is that they help us at the lowest tactical level. They find information that allows us to make decisions.”

Moments before soldiers storm compounds or search houses, drone crews relay messages to their commanders warning them how many fighters to expect to be there, and what weapons they will have.

On a search operation in Helmand, against a suspected bomb factory, drone crews directed troops to return to a compound they had already searched, after the operators spotted bodies hiding in a nearby treeline. Smaller versions of the Predator are flown from Kandahar and Camp Bastion. The British have hired a model plane enthusiast to help the drones 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 foolproof. America is investigating claims that its warplanes killed 89 civilians in an air strike in Herat last week. The Afghanistan President, Hamid Karzai, has already dismissed two senior Afghan officers for their role in the attack. It is 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 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.

— © The Independent, London