Eighteen months ago National Australia Bank opted for a restructure of its UK banking arm that David Thorburn, the UK chief executive said "will reduce the risk profile of the business and deliver returns that are both acceptable and achievable."This aspiration remains just that. NAB's UK bank reported cash earnings of £96 million for the year to September, compared with a loss of £139 million in 2012 .However, NAB's UK commercial real estate business, which NAB now reports separately and includes on the "group" balance sheet, incurred a second half cash earnings loss of £90 million, following a loss of £149 million in the first half. NAB shifted £6 billion in commercial loans, or one fifth of the receivables of its UK business, amid a retreat from the south of England.The return on assets of the core bank in the UK, at 0.25 per cent, is one third the return of the NAB group and one quarter of industry norms.The balance sheet of the core bank is shrinking, with customer deposits down £700 million over the year, in line with a further run-off in business loans.