Warmer weather lifted retail sales growth in the UK last month as shoppers grabbed grub for picnics and barbecues and kitted out their wardrobes with new outfits. The turnaround was driven by food and the total amount spent in shops rose 2.9% in the three months to the end of August, up from 2.6% reported the month before. Non-food sales fell by 1.7% over the same period, the same pace as July’s figure, according to the latest figures from the British Retail Consortium (BRC) and analysts at KPMG. Sales of clothing and gardening products also got a boost from the summery weather, according to the BRC, which represents most big retailers. However, spending on big-ticket items including furniture, household appliances and other homewares continued to decline as households kept a tight rein on budgets. Separate data from Barclaycard also released on Tuesday indicated spending on groceries rose by the fastest pace since March, with butchers and delicatessens enjoying a particular boost from alfresco dining in August. Barclaycard flagged strong spending in garden centres – its card holders paid out 8% more – the largest uplift so far this year. However, it cast doubt on the BRC’s positive findings on clothing, saying its credit and debit card holders continued to spend less on fashion than a year before. The card company added that clothing and accessories were among the most common areas where discretionary spending was being reined in, as 53% of shoppers planned to spend less. The outlook for Christmas was also under question as a survey for Barclaycard found more than a third of Britons anticipated that this Christmas would be more expensive than last year and one in five expressed concern about how they would keep up with those rising costs. Helen Dickinson, the BRC chief executive, said: “Sales growth picked up in August, particularly for food as people came together to host barbecue and picnic gatherings for family and friends, and for summer clothing and health and beauty products as people prepared for trips away and summer social events. “While computing did well as university students made the most of summer discounting and readied themselves for the new academic year, other back-to-school-related sales were weaker than normal as some families opted for secondhand purchases.” She called on Labour to use the autumn budget to update the business rates system to help retailers invest in growth: “Following a difficult summer for much of retail, and the possible weakening of consumer spending as energy bills rise come October, many will be waiting for the chancellor’s autumn budget before finalising their investment strategies.” Linda Ellett, the head of UK consumer, retail and leisure at KPMG, said the sunshine had not been enough to persuade shoppers to catch up with the total amount spent by this time last year. She said the figures reflected the “challenging retail environment that is likely to dominate for the rest of this year … Fashion retailers will be hoping sales growth continues as they look to dispose of excess summer stock as we head into the key autumn season.”