Sainsbury’s this morning revealed that total sales in its first quarter had risen by 3.6% (3.3% excluding fuel).Its like-for-like sales increased by 0.7% from a year earlier. Its market share is up 0.2% to 16.8% in the same period.The firm said sales at its convenience stores have risen by a fifth.Justin King, chief executive, said: “This has been a solid performance in what continues to be a tough consumer environment. During the quarter we lapped some of our strongest performance of last year, culminating in the Queen’s Diamond Jubilee, and have extended our track record to 34 quarters of like-for-like growth. We are the only major grocer growing market share, up 0.2% to 16.8%. This performance is driven by the hard work of our colleagues.”The supermarket said that during the quarter it had opened 19 convenience stores, refurbished a further 13, and was on track to deliver around two new stores per week for the year.