With his quiet manners and keen interest in sport Shehzad Tanweer seemed perhaps the most unlikely of the four 7/7 London bombers.

Born in December 1982 at St Luke's maternity hospital in Bradford, the young Shehzad - nicknamed Kaka, or little one, by his adoring parents - was never noted for radical political views among fellow pupils at Wortley High School, in Leeds.

Instead his passions were cricket, athletics, football and ju-jitsu, and he pursued his interests at Leeds Metropolitan University where he studied for a degree in sports science.

His parents ran first a curry takeaway, then a butcher's shop, and latterly a fish-and-chip shop, where Tanweer was working part-time at the time of his death.

The good-looking youth was simply seen as an observant Muslim. Friends said that he zealously attended mosque and avoided girls, and early in 2004 he - in common with millions of young Muslims the world over - made the haj pilgrimage to Mecca that is required by Islam.

Saj, a friend bearing an Arabic-script tattoo on his arm, said that Shehzad "was a quiet lad, religious. He used to go to every mosque in Beeston and there are loads of mosques around here."

Mahmood Khan, who worked in the chip shop, South Leeds Fisheries, said: "Shehzad was very religious. He used to go to the mosque a lot. He didn’t like girls. He didn’t have many friends but he was a nice, quiet person."

But he also used to hang around at the Hamara Youth Access Point, a drop-in centre for teens, which - it has since been alleged - was used as a recruiting centre for young Muslim firebrands by the leader of the 7/7 bombers, Mohammad Sidique Khan.

Clearly political awareness as well as religious zeal had already stirred in Tanweer when, on November 19 2004, he and Khan took a plane to Karachi to go and study in one of Pakistan's now notorious madrassahs, or religious schools.

Family in his ancestral village in Pakistan say that the young man fresh from England was fired with Islamist political rhetoric, boasting of wanting to die as a "holy warrior" and praising Osama bin Laden. Tanweer was outraged by incidents like the alleged desecration of the Koran in America's Guantanamo Bay prison camp, his family said.

There have been claims that the school Tanweer allegedly attended, 20 miles outside Lahore, was linked to the Lashkar-e-Taiba militant group which is banned in Britain. The madrassah denies knowledge of Tanweer.

Claims have also been aired that while in Faisalabad - his father's home region - Tanweer may have met a suspected organiser for Jaish-e-Mohammad, another banned group.

The video released today under the imprimature of al-Qaeda's in-house media group, in which Tanweer is seen ranting against the West, seeks to suggest that Tanweer not only had contacts with the fugitive al-Qaeda leaders Osama bin Laden and Ayman al-Zawahiri - who are believed to be in hiding in Pakistan - but that the London bombing plot was co-ordinated by al-Qaeda.

Britain's Intelligence and Security Committee report on the bombings, published in May 2006, said "it is assessed as likely" that Tanweer and Khan "had some contact with al-Qaeda figures" in Pakistan. The intelligence services reported also that the pair had "some from of operational training" in Pakistan.

Tanweer and Khan flew back to England together after three months in Pakistan, on February 8 2005. The pair were in a group of young British Asians photographed together on a white water rafting trip in Snowdonia National Park in Wales, on June 4. Barely a month later, they were dead.

In the days before the atrocity, Tanweer dyed his hair and eyebrows light brown. He hired a red Nissan car, and together with Khan and fellow bombers Hasib Hussain and Germaine Lindsay he drove south towards London.

Shortly before 9am on July 7, Tanweer carried a bomb in a rucksack onto an eastbound Circle Line train, and detonated his explosives between Liverpool Street and Aldgate, killing seven people and himself, and injuring many more. He was identified from body parts.

An uncle, Bashir Ahmed, 52, speaking outside the fish-and-chip shop run by Shehzad’s father, Mumtaz, said the young man had done a "terrible thing". But he did not blame his nephew for the bombing, saying instead that it was the fault of "forces behind him".

He said: "Shehzad had never been in trouble before. So what drove him to do it? It can’t be him. It must be something else behind him.

"It has come as a complete shock. He was respected by everybody and respected everybody in return. We were respected by the community — but how is the community going to treat us now?"

After the bombings, police recovered Tanweer's rental car from Luton station. In it they found 16 other bombs, including homemade nail bombs - plastic bottles full of explosives packed around with roofing tacks.

Tanweer's remains were buried at the shrine of a local Islamic saint in his ancestral village on October 27. He was found to have left an estate valued at £121,000 after taxes and debts.