Sir Graham Melmoth, Co-op Group chief executive, said: 'Our two operations have enormous but different strengths and should be pulling together to increase our share of the financial services market. Common leadership will help us achieve that goal.' Melmoth said cross-selling - the holy grail of the banking world - was 'minimal' at present within Co-operative societies. Few bank customers, for example, are given information about the insurance arm's products or vice versa.