UK grocers saw their best four-week sales period of 2012 in August as the London 2012 Olympics and good weather boosted growth, according to new figures.

During the four weeks to August 18th 2012, aggregate sales growth across UK supermarkets jumped 3.5 per cent year-on-year, according to data company Nielsen, while sales volume increased by 1.7 per cent year-on-year.

Such figures follow an 18-month trend of declining unit growth and the positive public reaction to the Games has also contributed to a strong performance in the sales value of soft drinks and confectionery, which rose ten per cent and eight per cent respectively over the period.

Mike Watkins, Nielsen UK‘s Head of Retailer Insight, explained the figures, saying: “Retailers have clearly looked to maximise the sales opportunity around the London 2012 Olympics.

“Although promotional activity has remained unchanged at 35% of FMCG sales, the continual use of money-off vouchers and coupons has marked a differing approach by retailers this summer.

“This has helped to increase shopping basket spends and, in return, given shoppers further savings at the checkout. Tesco, in particular, had some very attractive offers during July and August which will have helped to increase the frequency of shoppers‘ visits.”

Tesco, , has fared better than in recent months as it seeks to improve its market share in an increasingly crowded market, though remains behind key competitors.

Of the big four, Morrisons reported the slowest growth rate as its market share decreased 0.3 per cent to 11 per cent as its sales rose 1.4 per cent over the month, while competitor Asda performed best, increasing its share by 16 per cent as sales jumped 5.1 per cent year-on-year.

Commenting on the performance of individual grocers, Watkins added: “The Tesco sales recovery we first saw last month has continued and Tesco has now held market share at 29.1 per cent over the last 12 weeks.

“Discounters continue to grow sales faster than other food retailers, while Waitrose outperformed with a stellar sales growth of +12 per cent in the four weeks to 18 August – helped by shoppers spending more per visit on food and drink – making them this period‘s winner across the supermarket sector.”