The poison that killed former Russian agent Alexander Litvinenko was sprayed into his tea, a waiter who served the man's table at a hotel bar said in an interview published in a British newspaper yesterday.

The witness account in The Sunday Telegraph is the first to be made public, and provides new details on how the poison, a highly radioactive substance called polonium-210, might have been delivered.

The incident has strained relations between London and Moscow, and yesterday, the foreign secretary said Britain was "seriously considering all its options" in relation to the case.

Norberto Andrade, the head barman at London's Millennium Hotel, said he believes he was deliberately distracted as he tried to serve a gin and tonic to the table where Litvinenko was sitting with Andrei Lugovoi, a Russian businessman and former KGB agent, and two other Russians, Dmitry Kovtun and Vyacheslav Sokolenko, on November 1, 2006.

Though he did not see it happen, Andrade told the Telegraph he believes that at that moment the poison was sprayed into a pot of green tea on the table. He said investigators later told him that traces of the poison were found all over the table and floor and on a picture above where Litvinenko was sitting, leading him to conclude that the poison must have been sprayed.

"When I was delivering the gin and tonic to the table, I was obstructed," the paper quoted him as saying. "I couldn't see what was happening, but it seemed very deliberate to create a distraction. It made it difficult to put the drink down.

"It was the only moment when the situation seemed unfriendly and something went on at that point."

Later, after clearing the table, Andrade said he noticed that the tea looked more yellow than usual and became "thicker - it looked gooey."

Litvinenko later fell ill and was taken to a London hospital and died on November 23.

Alex Goldfarb, who co-authored a book about the case with Litvinenko's widow, said the appearance of the interview was significant because "it means the police and prosecutors have given up hope of having a trial. This witness has information that would have been useful at a trial."

(China Daily via agencies July 16, 2007)