Nationwide, Britain's biggest building society, grabbed its largest-ever share of the mortgage market last year and saw its profits jump as it continued to attract customers from discredited high street banks.
But the mutual suffered a huge increase in bad-debt provisions for its loans on commercial properties. These more than doubled from £247m to £493m, over a quarter of its commercial property loan book.
The retail business's growth more than countered this and headline profits rose 56 per cent to £475m. Gross lending rose by 17 per cent to £21.5bn, taking Nationwide's market share to 15.1 per cent.