Pakistan's Intelligence Service has long been accused of looking both ways, of tackling terrorists when they target Pakistan but actively supporting them when they target Afghanistan or India. But when 152 people were killed in the school in Peshawar, Pakistan's prime minister said it was time to change, that the country would no longer distinguish between 'good' and 'bad' Taliban. Retired general Asad Durrani used to run Pakistan's intelligence service. Are they really prepared to make enemies of their former friends? And what difference will it make?