The Co-op Group has once again outperformed the big four as recent overall grocery sales slowed following a record summer of spending, according to new Nielson data.

Over a four-week period ending 6 October, value sales growth across the sector slowed to +1.9%, compared to +2.4% sales growth in September, the figures reveal.

Comparing a 12-week period ending 6 October and the same in period of time in 2017, Morrisons (+2.2%) remained ahead of Sainsbury’s (+0.6%), while Tesco’s growth (+1.2%) also fell further behind Asda (+2.9%), with all four retailers promoting their respective price cuts over the last four weeks, Nielsen said.

However, the Co-op Group (+5.7%) continued to outperform the major supermarkets, following on from its 7.3% rise in value sales during the 12-week period up to September 8 this year. Among the main discounters, Aldi (+12.7%) outperformed Lidl (+7.2%) over the same period.

After the unseasonably-warm weather experienced this month, shoppers have begun tightening their purse strings in anticipation for the upcoming holiday season, according to Neilson.

Nielsen’s UK head of retailer insight, Mike Watkins, said: “The beginning of autumn has signalled an objectively disappointing, though not entirely unexpected, slowdown in sales. But keeping in mind retailers had such a strong summer period, its likely shoppers are pressing the reset button after a season of excess.

“The warmer weather also potentially has shoppers delaying the need to stock up and hunker down for the colder months. This paired with recent increases in fuel prices and energy bills, which are having an impact on household budgets has meant shoppers are becoming more cautious about their spending.

“It’s likely we won’t see this lull lift until the Christmas promotional period commences in two weeks’ time, which should give the industry much-needed momentum. With the recent weakened trading, there is a pressing need for retailers to encourage shoppers to get back into the shopping mode after schools break for half-term. Retailers will look to introduce lower prices in private label across core grocery staples to help drive volume sales - and brands will need to ramp up their promotional activity to counteract it.”