Morrisons has been told by the Advertising Standard Authority (ASA) to clarify claims it price matched the budget supermarkets.

The supermarket ran a TV ad campaign featuring Ant and Dec, in which it claimed a comparable grocery shop at Morrisons would be cheaper than all its major rivals - including Aldi and Lidl - or shoppers would be reimbursed the difference.

Aldi lodged numerous complaints with the ASA, claiming the advert would mislead shoppers and that a true comparison of products could not be achieved.

Today, the ASA told Morrisons not to repeat the ads "until it had provided consumers and competitors with a sufficient method to verify the references to the price-match scheme".

The watchdog also called on the supermarket make its methodology clearly accessible on their website as referenced in the ads.

Tony Baines, joint MD of buying at Aldi, welcomed the ASA's decision.

"This supports our view that these adverts did not provide consumers with sufficient price comparison data to enable them to make an informed choice," he added.

"Our own analysis shows that the Morrisons Match & More scheme did not price match Aldi. In our view, complex price promotions and price matching schemes of this nature are confusing, are not transparent and do not serve the best interests of consumers.

However, Morrisons was quick to point out that the ASA had dismissed four of the five complaints lodged against the advert.

"Soon after Match & More launch, Aldi lodged a number of complaints to the ASA regarding two specific adverts and their claims," it said in response.

"Four out of five complaints were dismissed, including one which crucially questioned the validity of the comparisons method used to match products and prices.

On the fifth point, which focused on clarity and availability of verification information and was upheld with the ASA, Morrisons group corporate services director Martyn Jones said:

"This was a reasonable request which we quickly resolved. Shoppers with a receipt have always been able to discuss their savings with our customer services team, but we have also made information clearer on our website. Overall, the ASA's ruling is a convincing outcome."

A Morrisons spokesperson also pointed out that the ads have not run for many months as the period of the campaign has finished.