John Lewis sales rose last week, boosted by back to school spending in its technology department.

Sales were up 5.7% to £77m in the week to August 19, the third week of John Lewis’ half year.

In the three weeks of the half so far, sales have risen 5.7%.

“Parents preparing for children going back to school and off to university helped drive a 13% increase in year-on-year sales of communications technology products such as computers and iPads,” said head of shop trade for the south and west Alison Smith.

Fashion sales were up 7.3%, driven by summer markdowns and cooler weather pushing cold weather and transitional purchases.

Womenswear was the fashion growth engine with a sales rise of 14.3% against menswear’s 5%.

At sister grocer Waitrose, sales rose 0.6% in the third week to £126.31m. In the three weeks they rose 1.1%.

“The cooler weather saw shoppers stocking up on typically autumnal items,” said IT director Mike Sackman. “Root vegetables were in demand, for example, as parsnip sales increased by 39%.

“In a similar vein, ready meal sales rose by 12.5%, hot pies by 34% and hot beverages by 7.5%.”

Across the partnership as a whole, sales rose 2.5% in the third week to £203.38m. In the three weeks, sales were up 2.8%.