Grocery sales growth slowed last month as cooler weather ground two months of surging supermarket sales to a halt.

The amount spent on groceries increased 2.5% year-on-year during the four weeks to August 12, less than half the rate of growth registered the previous month, according to the latest data from Nielsen.

Sales of soft drinks in particular suffered, slumping 6.1% year-on-year, against a strong comparable following the heat wave at the end of July 2016.

But the cooler weather provided a boost for the confectionery and packaged grocery categories, which grew 7% and 5.5% year-on-year respectively.

Nielsen’s UK head of retailer and business insight Mike Watkins said the slower rate of sales growth was a “reality check” for grocery retailers, as shopping patterns were “disrupted” by the weather and Brits going on holiday.

Despite the slowdown, rival data from Kantar Worldpanel suggested the big four grew sales for the fifth consecutive period – their longest run of growth since 2013.

Tesco grew sales quicker than its main rivals during the 12 weeks to August 13, with its 3% increase edging out Morrisons’ 2.6% advance.

Sainsbury’s sales rose 2%, while Asda, fresh from unveiling its first quarterly sales increase for three years earlier this month, enjoyed a 1.4% uplift.

Lidl’s market share hit a new high of 5.2% after its revenues spiked 18.9%. It now stands alone as Britain’s seventh largest grocer, having drawn level with Waitrose in last month’s figures.

Discount rival Aldi’s sales jumped 17.2%, according to Kantar’s figures, while Ocado was the fastest-growing grocer outside of the discounters.

The etailer posted a 12.6% increase in sales during the 12-week period.  

Nielsen backed up Kantar’s results, finding Tesco to be the fastest-growing member of the big four.

Britain’s biggest retailer posted a 3.2% uplift in sales during the 12-week period to August 12.

Closest rival Sainsbury’s registered a 1.8% increase, while Morrisons and Asda posted 2.2% and 1% uplifts respectively.

According to Nielsen’s figures, Lidl was again the fastest growing grocer, enjoying a 20.5% surge in sales to take its market share to 5.3%.

Discount rival Aldi’s sales advanced 14% as its market share hit 8%.

Iceland was the fastest growing non-discount retailer, posting a 6.2% climb.

Upmarket competitors Marks & Spencer and Waitrose recorded sales rises of 4.8% and 2.6% respectively, while the Co-op’s growth slowed to 0.8%.