Surging sales of winter garments have helped same-store sales at the Uniqlo casual clothing chain jump by 11.5% year-on-year in December.

Parent company Fast Retailing said today (4 January) that sales were helped by demand for innovative garments such as HeatTech underwear which uses heat-trapping fabric, and down jackets.

New large-format Uniqlo stores and unique lines like the +J Collection created with Jil Sander, have also helped the chain's sales grow.

Total sales at its 775 Japanese stores increased by 18.5%, while adding online sales lifted this figure to 18.8%.