Hamilton forced to 'raise the bar' for gruelling F1 title defence

A refreshed Lewis Hamilton insists he is prepared for the most gruelling Formula One season of his life as he attempts to deliver a third consecutive world championship for Mercedes. The Englishman romped to the third world title of his career last season with three races to spare to see off teammate Nico Rosberg. "The highlight of the winter break has been the break! No racing - just family, friends and snowboarding", he said as Mercedes launched the W07 Hybrid on the first morning of pre-seaso