Tesco has been rapped by the advertising watchdog after ads for its ill-fated Double the Difference price-checking campaign were branded “misleading” and “contradictory”.

The campaign, launched in March to combat Asda’s Price Guarantee, offered shoppers refunds worth twice the difference if their shopping proved cheaper at Asda than at Tesco.

Shoppers embraced the deal – and many took advantage of loopholes in the promotion to claim vouchers worth more than £100. Tesco was forced to step in and take action to limit the damage.

But complaints flooded into the Advertising Standards Authority after Tesco capped refund vouchers at £20.

Tesco disputed the complaints, suggesting that the £20 refund cap did not affect the average shopper.  But the ASA today ruled that the £20 limit was a significant restriction that would indeed affect the average consumer at Tesco.

The body also ruled that not including details of the restriction in some ads meant they were misleading.

The ASA concluded its findings by ordering Tesco to ensure that any significant conditions were included in the main body of any future advertising.