Tesco has launched a voucher offer just days after group chief executive Philip Clarke admitted coupons had proved the difference as it lost out to rivals over Christmas.

The UK’s largest retailer is offering £5 off a £40 shop next week when a customer spends £40 in store and online this week.

The campaign, backed by national press adverts, runs until January 22 with the voucher redemption running from January 23 to 29.

Last week Clarke said Tesco had lost out to “a lot of promotional couponing at Christmas elsewhere” while it ran its Big Price Drop price cutting campaign.

The campaign, named ‘A helping hand from Tesco’, uses similar language to a campaign from Asda pre-Christmas and directly mirrors Morrisons £5 off a £40 shop vouchers given away in The Sun and the Daily Mirror earlier this month.

A Tesco spokeswoman said: “We know that our customers will appreciate the vouchers now.”

An Asda spokeswoman hit back at Tesco’s campaign, labelling it a “gimmick”. She said: “While imitation is the sincerest form of flattery, Tesco’s attempt at imitation, misses the point.

“Our £5 off £40 at Christmas encouraged shoppers to go to our Asda Price Guarantee website where over four million in December alone saw how much more expensive Tesco were, day-in, day-out.

“They came, they checked, they found out the truth, and they stayed. Vouchers that promise lower prices instead of delivering them, are nothing more than a short-term gimmick.”

Planet Retail grocery analyst David Gray said: “This is a direct response to the mistakes it made over Christmas. It got its promotional mix wrong in focussing solely on price.

“I think we can expect a more flexible and balanced promotional mix in the coming year.”

Tesco is regrouping after a poor Christmas performance wiped £4.8bn off its stock market value last Thursday.