President Vladimir Putin probably approved a plan by Russia’s FSB security service to kill former agent Alexander Litvinenko, a British judge said today.

In a lengthy report, Judge Robert Owen said that he is certain Litvinenko was given tea laced with a fatal dose of polonium-210 at a London hotel in November 2006.

He said there is a “strong probability” that the FSB directed the killing, and the operation was “probably approved” by Putin.

Litvinenko, a former FSB agent, fled to Britain in 2000 and became a vocal critic of Russia’s security service and of Putin, whom he accused of links to organized crime.

Owen said Litvinenko “was regarded as having betrayed the FSB” with his actions, and that “there were powerful motives for organizations and individuals within the Russian state to take action against Mr. Litvinenko, including killing him.”

Moscow has always strongly denied involvement in Litvinenko’s death, and Russia refuses to identify the two main suspects, Andrei Lugovoi and Dmitry Kovtun.

Litvinenko, who had become a vocal critic of Russian President Vladimir Putin, died after he was poisoned with polonium-210, an isotope that is deadly even if ingested in tiny quantities.

He had fled from Russian to Britain in 2000 after breaking with Putin and his inner circle.