Ed Miliband is describing how to move from the "casino banking we have to the stewardship banking we need".
He said banks no longer care about the success of the firms they lend to because they are too concerned with making an "immediate return".
He said banks should have a "fundamental duty to serve the real economy".
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Labour leadership contender Yvette Cooper has accused Jeremy Corbyn of not being straight with people over the economy.
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