Former Russian spy Alexander Litvinenko died in a London hospital in 2006, after drinking tea poisoned with the highly radioactive material - polonium. But who wanted him dead, and why?

She suspected the presence of an even more powerful element. MARIE-NOELLE HIMBERT: Here, Po, Polonium is the first element that they discovered. CHRIS PACKHAM: It’s remarkable, isn’t it?

It might sound like an absolutely bonkers gimmick, but back in the days when we were still in our honeymoon phase with atomic ...