British supermarket Sainsbury's has today posted a sixth quarter of declining underlying sales in a row as a fierce price war and record deflation hurt the industry. 

The group trails market leader Tesco and Wal-Mart's Asda by annual revenue. 

It said today that sales at stores open over a year fell 2.1%, excluding fuel, in the 12 weeks to June 6, its fiscal first quarter. 

That was in line with analysts' consensus forecast but worse than a fall of 1.9% in the previous quarter. 

Sainsbury's, in common with its major UK rivals, is battling to win back ground against the discounters Aldi and Lidl through price cuts.

All players are also having to deal with record commodity-driven industry price deflation. 

The firm has previously guided that it expects like-for-like sales to be negative in the full 2015-16 year.

"Trading conditions are still being impacted by strong levels of food deflation and a highly competitive pricing backdrop," the supermarket group's chief executive Mike Coupe said. 

"Despite the challenging market conditions, we are confident that we are building on strong foundations and making good progress with our strategy," he added.

In November Sainsbury's outlined plans to cut the dividend and new store openings to fund an extra £150m in lower prices.

It is also investing in improving the quality of its products and expanding its non-food, online and convenience business.

The CEO said he was encouraged by some of the early trends the grocer was seeing in its key trading and operational metrics, notably growth in volume and transactions. 

He noted sales growth in Sainsbury's convenience business remained "double-digit", while clothing sales across the group were up over 5%. 

Industry data published last month showed that of Britain's big four grocers only Morrisons recorded a rise in sales over the 12 weeks to May 24.