Delta Force, the SAS and the shadowy war of misinformation

No, allied special forces have not been captured in Afghanistan. Yes, they are active. So what are they up to?

They are at the forefront of every war, tiny units of crack troops, inserted behind enemy lines as spotters for guided missiles and agents provocateurs.

The US and the Taliban agreed on one thing yesterday: no British or American special forces units had been arrested inside Afghanistan, despite breathless reports to the contrary that flashed around the world. But whispers from the White House that crack troops are already in action means that the spotlight is now on the British and American units entrusted with tracking down Osama Bin Laden's mountain hideouts.

What is also certain is that the leaks have infuriated the high commands on both sides of the Atlantic. By breaking its own code of silence the White House has possibly put soldiers' lives at risk. Several ex-SAS and commando officers have told The Independent on Sunday their mission is one of the most difficult in the world, and the risk of failure was already high before the media frenzy.

While there is much media glorification of the supposed exploits of British and US elite special forces, the real story is one of mishaps and botched operations. "People have got to sober up," said one ex-SAS officer involved ending the Iranian Embassy siege in London in 1980. "Expectations have to be pretty low in all of this."

Menzies Campbell, Liberal Democrat defence spokesman, warned that an early failure, such as the capture of reconnaissance parties, would severely damage the West's long-term chances of defeating the Taliban. "If American special forces have been captured already this will be an enormous propaganda coup for Bin Laden that he will no doubt exploit to the maximum," he said.

The White House's astonishing admission that US and British special forces were already deployed was, in all likelihood, prompted simply by a desire to satisfy a public craving for evidence that the US was already taking military action. There is no indication that the US plans a Gulf War-style land invasion of Afghanistan – quite the contrary. Instead, the focus is on small elite units from the US Delta Force or Britain's Special Air Service infiltrating Afghanistan with the help of anti–Taliban mujahedin groups to spy on the Taliban's major bases, and, in particular, locate and monitor Mr bin Laden's hideouts so that they can be bombed from the air.

Some of the units will be expected to "lay up" in total secrecy to help to guide "smart" bombs to their locations and supply eyewitness intelligence, which shock troops such as the Green Berets, US Rangers or British parachute regiments could use if they are deployed in a ground assault. "They will be looking for locations, looking for identification and looking at their operations," said Colonel Philip Wilkinson, a former British special forces officer. "They will continue with mobile surveillance, identifying all potential targets."

The US units most likely to be involved are the highly secretive Delta Force, an elite anti-terrorist regiment of about 2,500 troops based in a remote corner of Fort Bragg, North Carolina, and the Green Berets, an expert regiment of explosives, communications and linguistics specialists also based at Fort Bragg.

The Navy SEALs, the US version of the Special Boat Squadron, is another highly respected special forces unit which may be deployed for undercover reconnaissance operations.

Delta Force, set up by an SAS-trained US officer, Charlie Beckwith, based on the SAS model, has been training for action in Afghanistan since 1998. It has been involved in CIA operations tracking down the Colombian drugs baron Pablo Escobar and indicted war criminals in the Balkans.

Mark Bowden, a US military expert, said they have been preparing for this role for months. "They've known, full well, that this was a likely mission for them," he said. Military sources believe they are working closely with the SAS, which has the greatest level of operational expertise in the region of any coalition force. The SAS, based at Hereford, has a lot of experience in the Middle East and the Gulf, combating communist insurgents in the pro-British kingdom of Oman in the 1970s and, more recently, infiltrating Iraq during the Gulf War.

The SAS was never officially involved in Afghanistan, but some former officers have had direct experience there. During the Soviet Union's invasion 20 years ago, ex-SAS officers, such as the officer known publicly as Tom Carew, worked for the CIA and MI6 or as mercenaries, training anti-Soviet mujahedin forces. Such men will be essential to the intelligence of the SAS, the Pentagon, CIA and MI6. "They will be digging out all those people who've operated in Afghanistan before, and drawing on their experience," Col Wilkinson said.

Menzies Campbell said British role in the intelligence gathering would be crucial. "Afghanistan is an area which requires specialist knowledge and expertise which British special forces have as a result of their involvement with the resistance to the Soviet invasion," he said. "Maybe this was a task better left to the UK."

The SAS already has one of its four squadrons totalling about 50 to 60 soldiers in Oman for a major military exercise. A second squadron is likely to be added to them for the Afghan operation.

But some former officers are fearful that high public expectations will not be met. Afghanistan is a harsh, arid, mountainous country. Winter, when temperatures plunge to -40C, is four weeks away. The country has suffered four years of drought; food and water supplies are scarce and any Western soldiers would be extremely conspicuous. They are unlikely to be able to speak Pashtun, the local language. "It is possible to fade in in towns like Aden at midnight, but trying to do so during daylight in Afghanistan is ludicrous," said one ex-officer.

The SAS and US special forces have suffered significant and embarrassing failures in similar operations. The best-selling author Andy McNab became famous when his SAS unit was caught and tortured by the Iraqis during the Gulf War. His experience is a salutary lesson, a former colleague said. "The problems are goats and villages with dogs," he said. "That's how [McNab] got caught. Little boys with goats like going into the ravines and gullies that we like to hide in."

In 1993, the US Rangers lost 18 men and four helicopters in a botched attempt to arrest a Somali warlord in Mogadishu. In 1980, an attempt by the Delta Force to rescue US embassy hostages held in Tehran was thwarted after their inexperienced helicopter pilots botched the operation.

Some ex-SAS officers are confident of success. "The British are the best, that is all I am saying," Lofty Wiseman, author of The SAS Survival Handbook, said. 'They should be allowed to get on with the job and criticise them afterwards."