Watchdogs in London and New York have been poring over JP Morgan's trading positions as well as its systems and controls to ascertain what went wrong and whether it should face enforcement action. JP Morgan has taken the lead in the industry's fight back against new rules seeking to ban them from what has been described as "casino" banking. Chief executive Jamie Dimon has repeatedly railed against watchdogs, claiming their new rules will damage the banking industry and harm economic growth. A flurry of hurriedly convened meetings were held yesterday at JP's London headquarters, which only recently lost its most senior dealmaker, Ian Hannam, who quit to fight the Financial Services Authority's bid to fine him £400,000 for alleged market abuse. One banker said: "Heads will roll. This comes as a huge embarrassment to Jamie Dimon and one thing is certain: there will be blood." A sombre atmosphere pervaded the City of London and Canary Wharf.