It’s never been easier for a single mistake to define a whole lifeOccasionally, as a television presenter, you come across stories that make your blood run cold. The last time it happened, I was live on air and I virtually stopped speaking. I wish I could say the story was about some appalling human rights abuse or a new threat of global recession. But no. It was about a Russian newsreader, Tatyana Limanova, who committed a spectacular act of career self-sabotage by apparently flipping her finger at the camera live on air, immediately after a reference to President Obama. She seemed to have survived, at first, but within days her moment was on YouTube and the world was watching. Limanova had discovered the wrong kind of global celebrity, with the implicit added tease of a Cold War rerun.