IMPEACH BUSH

More than 3,500 insurgents have been "taken off the streets of Baghdad" by the elite British force in a series of audacious "Black Ops" over the past two years.

It is understood that while the majority of the terrorists were captured, several hundred, who were mainly members of the organisation known as "al-Qa'eda in Iraq" have been killed by the SAS.

The SAS is part of a highly secretive unit called "Task Force Black" which also includes Delta Force, the US equivalent of the SAS.

The prime targets have been those intent on joining the wave of suicide car bombers that claimed around 3,000 lives a month in Baghdad at the height of the terrorist campaign in 2006.

Using intelligence gleaned from spies and informers, Task Force Black has nearly broken the back of the terrorist network and reduced bombings in Baghdad from about 150 a month to just two.

But the success of the covert mission came at a price – six members of the SAS were killed and more than 30 were injured. Delta Force has suffered in the region of 20 per cent casualties.

A senior British officer told The Sunday Telegraph: "We took over 3,500 terrorists off the streets of Baghdad in around 18 months.

"You could say it was a very successful period. But the butcher's bill was high. The attrition rate is equivalent to that experienced by the SAS during the Malayan insurgency 50 years ago.

"The relationship between the SAS and Delta Force is very close," he added. "If anything, the attrition rate in Delta Force is higher. Two years ago the SAS made a donation to Delta Force’s 'widows and orphans’ fund of £10,000."

Senior sources denied that the SAS was taking part in "extra-judicial killings" and added that any incident which appeared to be in breach of the British Army’s rules of engagement would be investigated internally by the unit and by the Royal Military Police if any wrongdoing was suspected.

The source said: "There is no shoot-to-kill policy in Iraq, but there are only a few ways of stopping a suicide bomber. A British lawyer is present during the planning stages of every operation and our troops operate under British rules, not American rules."

The SAS began to concentrate almost exclusively on reducing the car bomb threat in Iraq at the same time that the US military launched its so-called "surge", which saw an additional 30,000 American troops move into the most dangerous areas of Baghdad, in early 2007.

Gen David Petraeus, the head of the US forces in Iraq, who is due to leave his post shortly, has praised the courage of the SAS.

He said: "They have helped immensely in Baghdad… they have done a phenomenal job."

In one incident, SAS troops rented a pink pick-up truck, removed their body armour to blend in with locals, and drove through the traffic to catch a key target.

"It was brilliant, actually," Gen Petraeus said. "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."