Laurent and Gabriel: a friendship that blossomed on an exchange programme

They were two students who came to London from France to study, and had agreed to extend their stay by a month because they were enjoying it so much.

Last night in France, friends and university teachers spoke of their shock and disbelief at the news of their deaths. Laurent Bonomo was described as a "born leader"; Gabriel Ferez as a "talented scientist".

"I knew Laurent very well," said Claude-Gilles Dussap, director of the Ecole Polytechnique Clermont-Ferrand, where M. Bonomo and M. Ferez had been studying for biochemical engineering degrees. "We worked together on a weekly basis. We would discuss student matters for two or three hours at a time. He was a born leader and a very good negotiator. And naturally, he was a gifted scientist. It was a pleasure working with him."

As part of their course, students are often required to spend time at a foreign university.

M. Dussap said: "I remember just before they left Gabriel told me, 'I'll be going to London with Laurent.' I could tell he was looking forward to the exchange."

The post-graduate students had not planned to go to Imperial College London together. But once they found out they had both been accepted, they grew closer and planned the four-month exchange programme together. They were researching protein chains in DNA.

M. Bonomo, 23, from Velaux, near Aix-en-Provence, was described as "intelligent" and "outgoing". He was active in the academic and social life of the university in Clermont-Ferrand, central France. Last year he was elected president of the university's student union. M. Dussap said his intelligence and concern for fellow students made him a perfect candidate for the position. M. Ferez, 23, from Prouzel, near Amiens, was described as a talented scientist with a bright career ahead of him. "Gabriel took his studies very seriously," said M. Dussap. "He was the type of person who thought before he acted. Once he knew what he wanted, he would set about getting it."

Classes have ended for the summer at the university. Many of its students are at foreign universities, on academic research programmes. M. Dussap said the deaths have led some students to return to France earlier than planned.

Sofiane, a student at the university, said he was sickened by the news. "They were really friendly guys," he said. "They only went to London to study and now they are dead. I thought it was a bad joke at first, but now I realise they're not coming home."

M. Dussap added: "There is only one word to describe the atmosphere at the university at the moment – shock. Pure shock. Laurent and Gabriel were exemplary students."

He said he had received a phone call from the French embassy in London on Monday evening. "They said something bad had happened, but wouldn't tell me what," he said. "On Tuesday I had a second call. That's when they told me that Laurent and Gabriel were dead. It was very difficult to accept. They will be missed."