Source and full story - BBC NewsUK police are investigating the poisoning of a Russian former security agent and critic of President Vladimir Putin living in exile in Britain.
Alexander Litvinenko, a former colonel in the KGB, told the BBC he fell ill after meeting a contact at a London sushi bar on 1 November.
Police say the 44-year-old is in a serious but stable condition in University College Hospital, London.
Clinical experts said he was poisoned with the highly-toxic MEHTUL thallium.

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