On November 1, 2006, 43 year old former spy Alexander Litvinenko was poisoned at the Pine Bar in London’s Millennium Hotel. He had been served a pot of green tea laced with a massive dose of Polonium 210. This radioactive isotope is five million times more toxic than cyanide and was used as a microscopic murder weapon. The poisoning was so potent that Litvinenko left a trail of radiation across London. Investigators found extreme readings on the hotel’s tea cups, the boardroom table where he sat

It's 10 years since the former Russian spy Alexander Litvinenko was poisoned and now a new documentary looks at one of the most complex cases in the history of Scotland Yard. Dan and Louise spoke to the journalist who made the documentary and Alexander Litvinenko's widow, Marina. | BBC Breakfast