The first-ever female chief executive of a FTSE 100 company, she oozed intelligence and charm. She could do no wrong. Five years on, investors are thinking again. Pearson has tumbled more than 65% since its 2000 peak and Scardino has issued her second profits warning in two months. She has 'lost her halo' and analysts, once starry-eyed, realise the 54-year-old is finding life just as tough as her male counterparts.