John Lewis sales fell 3.8% to £85.7m last week as electricals and home technology sales plunged 6%.

Home sales also dropped 4.4% over the week to January 13, although cookshop revenue rose 5.2%.

Fashion was the only category to experience growth – up 0.3% – driven by a 6% jump in womenswear. Women’s accessories advanced 3.4%.

Sales also dipped 0.3% to £121.7m at John Lewis’ stablemate, upmarket grocer Waitrose.

Ambient was the only category in growth – up 0.2%. Chilled fruit, veg, bakery, meat, fish, frozen and dairy sales fell 0.5%, while home and general merchandise sales dropped 2.3%.

Waitrose said healthy-eating New Year’s resolutions appeared to be in full swing as fish sales soared. Pre-packed fish sales rose by 10% and fish counter sales were up 7%.

Last week, the grocer began trialling a personal nutritionist service, designed to provide customers with tailored dietary advice, in its Canary Wharf and Kingston-upon-Thames branches.

Waitrose supply chain director Wim Van Aalst said its shoppers also have their eyes set on spring, with outdoor plant sales soaring 44% and indoor plant sales up 10%.