Tesco is mounting a fightback against Sainsbury’s Brand Match voucher scheme with a coupon-at-till reboot of Tesco Price Promise, its disaster-plagued price comparison scheme.

It has launched a trial at its 38 stores in Northern Ireland, giving customers a voucher at the till for the difference if their basket is more expensive than at Sainsbury’s or Asda.

The retailer is understood to be lining up a rollout across the UK after Christmas in a move that would see the scheme extended to cover Morrisons, which does not have stores in Northern Ireland.

Significantly, while Sainsbury’s scheme only compares the price of brands at Tesco and Asda, Tesco’s new Price Promise also compares the price of own- label lines. Customers must buy at least eight items and a £10 limit has been set on each voucher.

The Price Promise is based on daily web scans of Asda and Sainsbury’s grocery websites by an external agency.

The evolution of Tesco’s Price Promise

After dismissing Asda’s Price Guarantee as complicated and unwieldy, Tesco launched its own Price Check in February 2011 offering customers ‘Double the Difference’ if the price of their shopping was cheaper at Asda.

After just two months, this was replaced with a scheme paying ‘Just the Difference’, as shoppers exploited loopholes in the promotion to claim vouchers worth more than £100. Tesco was then rapped by the ASA for misleading shoppers after quietly introducing a £20 cap.

Tesco and Asda found themselves trumped by Sainsbury’s Brand Match scheme which launched in October 2011 and gave customers instant vouchers at the till on branded product comparisons.

Tesco’s scheme was relaunched as the Price Promise in June this year. With a £10 voucher limit, it was originally open to Clubcard customers only.

The new system comes complete with online rebranding, with the trial in NI backed by marketing instore, plus TV and outdoor ads.

Experts said Tesco would have had to make a “very significant” investment in new technology to develop the system.

Although Tesco has marketed the trial heavily, a mystery shopper for The Grocer reported teething problems when he visited Tesco’s Lisnagelvin store, in Londonderry, this week.

“There was a lot of confusion among the staff,” he said. “I was told that the scheme did not work on own-label goods, but when I went to customer services they said it did. I did end up with £1.18 off my shopping, though.”

Sainsbury’s also trialled Brand Match in Northern Ireland in August last year, before rolling it out across the UK two months later. The scheme’s success has contributed to Sainsbury’s market-leading performance this year.

“Brand Match’s strength is that customers receive their vouchers at the till,” said Bryan Roberts, an analyst at Kantar Retail. “Tesco hopes the killer blow will be that it can do that but also extend it to own label.”

A leading consultant added: “If this is a case of open and honest value, then it’s a good thing, but if it’s smoke and mirrors, it would be another big mistake.”