Fifteen years ago, Putin critic Alexander Litvinenko, who had fled Russia to safety in Britain, was hospitalised with a mystery illness after a business meeting with two Russians in a London hotel. A haunting photo of Litvinenko shocked the world, and three days later he was dead, poisoned by radioactive Polonium-210. Award-winning Daily Mail crime writer Stephen Wright talks to his widow Marina Litvinenko  in Part One of a two-part podcast about the moment she realised that her husband had been poisoned, her 15-year quest for justice, and her husband’s powerful deathbed message to Vladimir Putin, ‘You may succeed in silencing one man but the howl of protest from around the world will reverberate in your ears for the rest of your life.’