Inditex, which owns Zara stores, said a polka-dot dress that became the summer sensation helped the world’s largest clothes retailer withstand a tough retail market, driving a 7 per cent sales increase. The Spanish group generated €12.8bn in sales in the first half as like-for-like sales rose 5 per cent and gross profit rose 7 per cent to €7.3bn. “The 8 per cent gain in Inditex shares over the past month has heaped pressure on the retailer to outperform rivals.