THE Russian president, Vladimir Putin, has expressed his anger at Britain’s failure to gag Alexander Litvinenko in the final hours of his life, the cabinet has been told.

Margaret Beckett, the foreign secretary, told ministers that the Russian government had “taken exception” to the poisoned former spy’s deathbed letter accusing the Putin regime of murdering him.

This weekend a potential suspect — Andrei Lugovoi — admitted he had been contaminated with the radioactive poison polonium-210 but insisted: “I’ve been framed.”

Beckett, who spoke to her Russian counterpart before Thursday’s cabinet meeting, said the Russians had “seemingly failed to understand” that Litvinenko was under police supervision rather than in custody.

Amid signs that his death could cause a diplomatic row, Tony Blair concluded the cabinet meeting by saying “the most important issue” was likely to be Britain’s long-term relationship with Moscow.

Another minister present said: “It caused some alarm that this case is obviously causing tension with the Russians. They are too important for us to fall out with them over this.”

Putin’s aides see Litvinenko’s letter, in which he described the Russian president as “barbaric and ruthless”, as a carefully orchestrated public relations stunt, timed to coincide with the leader’s appearance at the Russia-European Union summit in Helsinki.

Foreign Office officials yesterday confirmed the Russians had raised the issue of Litvinenko’s letter with Beckett and British diplomats. Until now, the government has admitted only that the Russians had agreed to assist Scotland Yard with its inquiries.

John Reid, the home secretary, told the cabinet “not to make assumptions” about Litvinenko’s death, pointing out that the former spy had been “involved with” organised crime as well as the KGB, Chechens and exiled Russian oligarchs.

With more than 200 people tested for suspected radiation contamination and 3,000 calls handled by NHS Direct, Patricia Hewitt, the health secretary, said there was a risk the NHS could be “overloaded”.

Reid said the contamination by polonium-210 — a highly radioactive isotope, which has so far been found at 12 sites in London — could have come from more than one person.

The potential suspect Lugovoi told The Sunday Times he was the mystery businessman who had visited locations across London since tested positive for radioactivity, including the Sheraton Park Lane hotel. According to other sources, he also went to the offices of Boris Berezovsky, the dissident Russian billionaire.

The radioactive trail suggests that Lugovoi, also a former spy, was contaminated with polonium-210 as early as October 25, about a week before Litvinenko was poisoned, probably at a sushi bar in Piccadilly.

Lugovoi denied he and two business associates, Dmitri Kovtun and Vyacheslav Sokolenko, were involved in any plot. All three men met Litvinenko on November 1, the day he was poisoned. “We suspect that someone has been trying to frame us,” said Lugovoi. “Someone passed this stuff onto us . . . so as to point the finger at us and distract the police.” He also suggested they could have been contaminated by Litvinenko.

Lugovoi, who has been in contact with Scotland Yard, said he had flown to London from Moscow on October 25, checking into the Sheraton Park Lane. It may explain how the hotel was contaminated, as Litvinenko did not visit it on November 1.

During a second trip to London to watch the Arsenal-CSKA Moscow football match, Lugovoi, Kovtun and Sokolenko met Litvinenko at the Millennium hotel in Mayfair. Yesterday police mounted a search for polonium in the part of the Emirates stadium where Lugovoi had been sitting and gave it the all-clear.

By the time of the meeting at the Millennium hotel, Litvinenko is thought to have already eaten at the Itsu sushi bar with Mario Scaramella, an Italian security expert. Yesterday the bar’s manager was contacted by police for a second time.

Litvinenko fell seriously ill shortly after this meeting with Scaramella. As he lay dying, he said he believed Lugovoi was a key suspect.

Alexander Goldfarb, Litvinenko’s friend, said: “He obviously suspected Lugovoi. He suspected Scaramella too, but he suspected Lugovoi more. That is why when he was ill, he never put that meeting with Lugovoi and his associates into the public domain. He wanted to lure him back to London when he got better.”

Scaramella was yesterday at University College hospital after he tested positive for radioactivity. He was said to have no symptoms of radiation sickness, but Sergio Rastrelli, his lawyer, said: “The doctors have told him polonium always has potentially lethal effects. He either inhaled or ingested polonium. He was not contaminated by Litvinenko.”

Litvinenko’s wife, Marina, who has also been contaminated, is showing no sign of illness and her level of radiation is described by police sources as “absolutely minimal”.

Police sources confirmed the dose administered to Litvinenko was “at least 100 times” the amount needed to kill somebody.

The sushi bar is the most likely place that Litvinenko and Scaramella were poisoned, but detectives do not know how the radioactive material was administered. They are not ruling out the possibility that the two men were poisoned separately elsewhere.

Detectives have told ministers they are closing in on a suspect. They say he is a businessmen who travelled from Moscow to London before November 1 but refuse to say whether Lugovoi is the suspect.

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