SANA’A, Yemen — Osama bin Laden is a workaholic who will always be one step ahead of Western intelligence, his former bodyguard has told the Daily Telegraph.

Many have claimed intimate knowledge of Mr. bin Laden during the years. But in the case of Nasser al Bahri, a bearded and slightly portly 35-year-old taxi driver who lives in Yemen, the claim is not tainted by exaggeration.

For four years Mr. Bahri fought in Afghanistan with Al Qaeda and served as bodyguard to a man he remembers affectionately as “the Sheik.”

His experience makes Mr. Bahri of intense interest to the FBI and CIA, but they have so far failed to persuade the Yemeni authorities to deport him for questioning.

“The thing I remember most about the Sheik is that he was very, very active,” Mr. Bahri said. “From the start of the day, before dawn when he began his prayers, to late at night he was always doing something, never resting. We were not living in a comfortable environment but that did not stop him from all the time working, thinking and planning. “After prayers came administration and after administration came meetings with distinguished visitors, sometimes secret visitors, but all day he never stopped.”

Sitting in a quiet corner of a hotel restaurant in Sana’a, the capital of Yemen, Mr. Bahri shook his head at the colorful claims about his role protecting Mr. bin Laden in the late 1990s. He did not screen Mr. bin Laden’s food for poison and he was not under orders to shoot Mr. bin Laden dead if he was about to fall into enemy hands.

Instead, he acted as an armed personal assistant, carrying his baggage, making sure his satellite communications were working, and chivvying the various other members of the entourage, from cooks to drivers. “To be honest, I have never killed a man,” Mr. Bahri said.

“The worst moment came when a Sudanese man came for a visit and he became very rude and disrespectful to the Sheik. I had to grab his hands, handcuff him, and take him away. But even then the Sheikh told me to let him go.”