The recent barrage of price and promotion-related advertising has sparked a massive increase in the number of complaints about supermarkets to the UK’s advertising watchdog.

The Advertising Standards Authority received 791 complaints about supermarket ads in 2011 – almost double the 380 complaints recorded the previous year.

It attributed the rocketing number of complaints to the supermarkets’ increasingly aggressive advertising campaigns.

“The highly competitive nature of the sector, particularly during an economic downturn, prompts more promotions around best value and price comparisons, which prompt more complaints,” said an ASA spokeswoman.

The big four all launched high-profile price campaigns in 2011. Asda and Morrisons were first up with the 10% price guarantee and the Price Crunch at the start of the year, followed by Sainsbury’s and Tesco with Brand Match and the Big Price Drop in the autumn.

Shoppers and rivals have been quick to complain about claims they perceive to be misleading. This month, the ASA ordered Asda to scrap ads claiming “only one supermarket is always 10% cheaper” following a complaint from Tesco.

However, the spike in complaints only resulted in a small number of ads being banned – and fewer than in 2010. The ASA upheld or partly upheld seven complaints about supermarkets in 2011 compared with nine the year before.