Debenhams has flagged a double-digit price increase in outerwear for autumn 2011 and expects prices overall to increase by between 4% and 6% before VAT over the year.

Chief executive Rob Templeman said that increasing commodity prices would result in price increases next season for outwear, which requires more material and higher quality fabrication as well as more labour and time to produce.

The department store group, which recorded market share gains across all categories despite a fall in like-for-like sales over the 19 weeks to January 8, will re-engineer product to ensure opening price points remain competitive.

Group like-for-likes dropped 0.3% including VAT in the period, and fell 1.3% excluding the sales tax. The bad weather impacted like-for-like sales by between 2.5% and 3%, costing Debenhams £30m in lost sales in the run-up to Christmas.

However, margin remained ahead of last year and Templeman said that terminal stock would be at an all-time low at the end of the first half.

Investec analyst Katharine Wynne revised her full-year like-for-like sales forecast from -0.5% to -1%.

Wynne left her margin assumptions unchanged “as Debenhams has once again demonstrated its ability to manage high/low pricing and terminal stocks well, even in the event of an unprecedented weather impact over peak”.