But as she spoke, Lai Thi Kim Thoa, 51, was mourning the end of her son’s dreams.

Mr Tu, 25, a student of architecture at Kingston University, was on the eastbound platform of Earls Court Station during the rush hour on November 23. He was standing next to a group of teenage members of Queens Park Rangers Football Club. The footballers appeared to be “play fighting” when one of them, 17-year-old Harry Smart, fell from a friend’s shoulders on to the tracks, taking Mr Tu down with him into the path of an oncoming train.

The young footballer survived with serious head and leg injuries. The Vietnamese student died. It would be two days before the news travelled the 5,700 miles (9,200km) to his home in the Vietnamese capital, Hanoi. Yesterday Buddhist monks chanted prayers in the family home.

“He particularly wanted to study in Britain to learn about British architecture,” said his father, Vu Quang Tam. “He thought that England was the cradle of architecture and he studied the internet and books to learn more about the styles.”

Mr Tu had another reason for choosing London as his place of study — its safety compared with the chaotic cities of North America. “He knew about the Tube bombings but he thought that England has a good security system and that he would be safe in London,” said Mr Tam. “He wasn’t worried about getting into trouble or being beaten up. He never complained about life there.”

In any family, the loss of a son would be devastating, but the story of Vu Quang Hoang Tu is filled with cruel ironies. He was the elder of two sons, and his family had placed spent their life savings on his studies in London — a year-long English language course, which he had successfully completed, and a master’s degree in architecture. “The courses were very expensive,” says Mr Tam, who has just retired at 59 from his job as an accountant with the Hanoi city government.

“The English course cost $7,000 (£3,500) and the master’s cost £9,200. It took us all our working lives to save up this money — more than 30 years of savings. We have no money left to spend on our second son. We had hoped that after graduation Tu would return and get a good job and pay for his brother to continue his education. But now . . .”

Mr Tu was an exceptionally bright, promising and decent young man. He grew up in Hanoi. Like all Vietnamese of their generation, his parents have lived through great suffering. Mrs Thoa, a medical technician, survived a notorious US bombing raid on her hospital in Christmas 1972 during the Vietnam War.

“Tu was born into a very traditional family,” said his father. “We believe in having a good education. We follow Buddhism, so from a young age he was taught to help others. He was very respectful of his parents and kind to his friends and helped them when they were in trouble. He used to help the younger students with their studies. He was a very good son and very intelligent.”

He graduated with an architecture degree from a Hanoi university, then left for London in November 2005. His family supported him for two months, but he found a job washing up in a Vietnamese restaurant. He was a good looking young man, unusually tall at 181cm (5ft 11in), and he arrived in London with long hair in the style of a Hanoi Bohemian.

“After a while in London he shaved his hair short,” his father remembers. “He realised that people in London didn’t like the long-haired style.”

He would speak to his 20-year-old younger brother, Vu Quang Hoang Anh, three or four times a week, and once a week to his parents.

He also wrote letters, and it is these that his parents weep over as they sift through photographs — Tu standing on his beloved Tower Bridge, and sitting on a lion in Trafalgar Square. In Hanoi he played basketball, but in Britain he became a passionate footballer.

“In London he was the goalkeeper for the Vietnamese students’ football team,” adds Mr Tam.

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