German budget supermarkets Aldi and Lidl continued to rattle the cage of the 'big four' over the summer period, recording a performance far in excess of their bigger, more established rivals.

In fact, it was the smaller of the two that faired best in the 12 weeks to 14 August - Lidl reporting a 12.2% rise in like-for-like sales. But Aldi wasn't too far behind, staying strong on 10.4%.

Contrast that with the performance of the likes of Tesco, Sainsbury's, Asda and Morrisons, and you really get a sense of just how well the German firms are doing. The best of these four was Tesco. Sales were down 0.5% on the same period in 2015. Sainsbury's was just behind with a 0.6% fall, while Morrisons' sales were down 1.8%. Asda, on the other hand, saw a drop of 5.5%.

Industry research firm Kantar Worldpanel said that despite the struggling big four, it was a positive period overall for the supermarket industry, largely boosted by a few weeks of hot weather and sunshine.

Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel, said: "The sun's eventual appearance was a welcome boost to the market after a delayed start to the summer.

"Frozen confectionery sales grew by 23% in the last month, while chilled drinks increased by 10%."

The figures also revealed a drop in promotional sales, as the big four moved towards lower pricing to compete with likes of Aldi and Lidl.

Mr McKevitt said: "Fewer promotions doesn't mean consumers are paying more for their shopping but does reflect the renewed focus on own-label lines which is visible across the market."