UK had the highest level of debt after Japan, an international study by management consultancy McKinsey found Britain faces a difficult challenge over the next decade as it slowly adjusts to an economy less dependent on debt-fuelled growth, according to new research by consultancy McKinsey. An international study found Britain had the highest level of debt after Japan, that the debt had risen over the past three years to more than 500% of national output, and that on current trends it would take until 2020 for UK households to return debt levels to the pre-bubble trend