In London's MI5 headquarters a scandal is brewing that could disgrace the entire intelligence community. The Downing Street superforecaster-a specialist who advises the Prime Minister's office on how policy is likely to be received by the electorate-hasdisappeared without a trace. Claude Whelan, who was once head of MI5, has been tasked with tracking her down. But the trail leads him straight back to Regent's Park itself, with First Desk Diana Taverner...