The British Army’s SAS Regiment, which played a vital role in defeating al-Qaeda in Iraq, is now arriving in Afghanistan in one of the biggest deployments of UK special forces since the Second World War.

Two squadrons from 22 SAS are being sent to Afghanistan now that Britain’s combat role in Iraq has been wound up, to carry out clandestine operations against the Taleban.

The deployment of the SAS, which will be joining the Special Boat Service (SBS) already serving in southern Afghanistan, represents a mini-surge of troops to add to the 700 regular British soldiers going out for a four-month period to provide extra security during the presidential election.

The switchover of the SAS from Iraq to Afghanistan has coincided with the replacement of General David McKiernan, the overall American commander of Nato’s International Security Assistance Force, by Lieutenant-General Stanley McChrystal, former commander of US Special Operations, who is expected to launch missions to starve the Taleban of fighters, funds and arms.

The impact of the SAS in Baghdad in eliminating the threat from alQaeda and persuading Sunni insurgents to swap sides and become informants helped to bring the war to an end. In a recent interview with The Times, General Sir Richard Dannatt, the head of the Army, said that the coalition special forces, including the British units, had taken on al-Qaeda “and their mass-suicide tactics . . . full square” and had defeated them in Baghdad. “Al-Qaeda didn’t defeat itself in Baghdad. It was defeated, substantially defeated,” he said.

Working closely with a specially trained unit of 12 Iraqi commandos, the SAS in Baghdad and Anbar province crippled at least two car bomb networks, killed or captured hundreds of key targets and took part in multiple rescue missions to save hostages such as Norman Kember, the British peace activist. The SAS sprang into action hours after scores of gunmen in police uniforms kidnapped Peter Moore, a computer consultant, and his four security guards from a Finance Ministry compound in Baghdad on May 29, 2007. SAS troopers were deployed to Sadr City in the hunt for the five, raiding suspected properties night after night, but to no avail.

While the majority of Britain’s military effort was based in Basra, the SAS set up headquarters inside Baghdad’s fortified green zone, working closely with Delta Force, its US counterpart. Members of the squadron also rotated into Basra, where they teamed up with US Navy Seals to hunt Iranian-backed Shia militias.

Delta Force and the SAS learnt from each other. The Americans were impressed by the ability of the SAS to get up close to a target before striking — a technique known as “close-target recce”. Members of the team would apparently even dye their skin brown and hair black, don fake gold watches and wear Iraqi clothes to look like locals, and approach a target.

The SAS principally hunted car bomb networks in Baghdad, a task it pursued up until its final days, taking out two of the six cells in existence. The British efforts earned particular praise from General David Petraeus, the American commander, when he led the multinational force in Iraq. “Who dares wins,” he said, quoting the SAS motto. “They have exceptional initiative, exceptional skill, exceptional courage and, I think, exceptional savvy. I can’t say enough about how impressive they are in thinking on their feet.”

The unrivalled covert operational experience of the SAS in Iraq is now being added to the expertise of the SBS, which has been Britain’s main special forces component in Afghanistan since 2006, alongside the SAS’s Territorial Army units, 21 SAS and 23 SAS.

The arrival of the SAS from Iraq, accompanied by additional specialist troops from the Special Reconnaissance Regiment (former undercover surveillance teams from the counterterrorist campaign in Northern Ireland), and the Special Forces Support Group (formerly the 1st Battalion The Parachute Regiment), will make a substantial difference to Britain’s military campaign in Helmand province.

• Two British servicemen who died after being wounded in separate incidents in southern Afghanistan this week were named by the Ministry of Defence yesterday as Lance Corporal Robert Richards, 24, of the Royal Marine Armoured Support Group, and Lance Corporal Kieron Hill, 20, of the 2nd Battalion The Mercian Regiment.

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