John Lewis & Partners has blamed the “unseasonably” warmer weather for its tumbling weekly sales.

The department store chain’s total sales fell 12.4% for the week to September 21, with it blaming warmer weather impacting “sales of new season products”.

Fashion sales during the week fell 12.3%, compared with a 1.2% rise for the same period the previous year. Beauty sales registered a 0.7% increase after price-matching a competitor’s promotion.

Electricals and home technology sales declined 11.4%, but the retailer said the “demand for new communications technology product launches picked up over the weekend”.

John Lewis home sales fell 13.4%, but its own-brand house range “continues to perform well” with customers shopping for ‘Off to University’ ranges.

Waitrose & Partners’ total sales during the period fell 1%, driven by a 6.6% decline in home and general merchandise sales. Non-ambient food sales decreased 1.8%, while ambient food registered a slight 0.6% uptick during the same week.

John Lewis Partnership’s total sales for the week fell 5.6% to £202.2m, down from £214.3m for the comparable period the previous year.