Sainsbury's boss Justin King was in a bullish mood this week as he boasted that the supermarket was strongest placed of all the big four to capitalise on future growth.

King also claimed the latest advertising campaigns from its rivals were playing straight into Sainsbury's hands. "There is a big difference in the advertising reels of all major grocers today from those of 12 months ago," he said. "Everyone is advertising quality in some way, shape or form and that's great for us, because we are confident we have the best quality and best value food of any of the big four."

Sainsbury's had achieved its 123% rise in pre-tax profits to £194m for the 28 weeks to 7 October through its core strengths: food and food quality, King added. Like-for-like sales were up 6.2%. And TNS Worldpanel results out this week show Sainsbury's has increased market share from 15.6% to 15.9%.

"We've improved our availability, which was our most visible failing, and we've moved prices down," said King. "We are seeing a continuing shift in consumer attitudes towards quality. We believe we have been instrumental in this shift."

Reaction to the results from City analysts was mixed, however. "Sains­bury's interims were in line with our numbers and consensus and showed that the recovery is well on track," said Oriel's Jonathan Pritchard, but he added that while sales should continue to motor, he had doubts about operating margins.

David McCarthy at Citigroup said growth in operating margins was disappointing. "The operating margin rose by 37bps to 2.43%, below our expectation of 2.65%. The company may be pleased with this, but Morrisons' margin is now at 2.7%, having started from a lower level."

Sainsbury's has added £1.3bn sales at the midway stage of its three-year recovery programme, just more than half-way towards its £2.5bn target by March 2008.

McCarthy said he believed Sainsbury's would struggle in the second half of its recovery as its comparison figures would start to get tougher.