Jamie Dimon, the chairman and chief executive of JP Morgan, said he wants 'London to be our happy home for a long time' - Julia Demaree Nikhinson/AP PhotoThe boss of JP Morgan warned Andy Burnham against launching a tax raid on banks as he urged the new Prime Minister to focus on growth. Jamie Dimon said there would be "adverse consequences" if Mr Burnham targeted lenders with fresh windfall taxes to help fund his spending plans. However, Lord Jim O'Neill, a former Goldman Sachs chief economist who has been helping Mr Burnham prepare his economic agenda, has poured cold water on the suggestions. He has suggested that the new Prime Minister should balance the books through lower spending rather than tax rises. 'I'm praying Labour get policy right'Mr Dimon said he wanted to see Mr Burnham succeed and the UK thrive.