Supermarket grocery sales were up 1.5% in the four weeks ending June 18, according to the latest figures from NielsenIQ, thanks to a boost from the Platinum Jubilee weekend.

The Jubilee, which took place during the week ending June 4, boosted sales by 3.7%, NielsenIQ said, with Champagne up 47% and sparkling wine up 40%. Recent warmer weather also caused a slight uptick in sales.

However, the Total Till data also revealed that volumes declined by 5.5% in the four-week period, as shoppers manage their spend in the wake of the rising cost of living.

Rising prices are leading shoppers to consider cheaper meal alternatives, the insights company said, with sales increasing for frozen poultry (+12%) and rice and grains (+11%). In contrast, sales of beers, wines and spirits (still impacted by the slow reopening of the hospitality industry a year ago) fell 9.7%.

Elsewhere, online shopping sales fell 12% compared to a year prior and in terms of retailer performance, NielsenIQ said M&S “continues to have strong momentum” while Tesco is the only one of the big four to grow. However, Aldi and Lidl are still the fastest growing food retailers and their combined market share has now hit 19.1%.

“Shoppers are starting to make different choices in how to compensate for their rising cost of living,” said Mike Watkins, NielsenIQ’s UK head of retailer and business insight. “For some households, the way to save money is to buy cheaper products and our analysis suggests that some of the increased cost of an overall basket can be mitigated in this way.

“For one in four households this goes further and includes monitoring the overall cost of their shopping basket, opting for private label, waiting for their preferred products to be on offer or seeking out their favourite brands at value retailers such as Home Bargains, B&M or Poundland. According to NielsenIQ data, for the 15% of households who now consider themselves to be ‘strugglers’, almost a quarter of this cohort will stop buying certain products altogether and 28% will shop more at Aldi and Lidl.

Watkins said the outlook for the next four weeks is for further pressure on shopper spend.

“Whilst there are some major sporting events over the next few weeks, such as Wimbledon, the F1 and the Women’s Euros, incremental volume growths to the end of July will probably remain subject to the vagaries of the weather. And in the meantime, as shoppers remain cautious, retailers will continue to offer differential price cuts and savings for their most loyal shoppers.”