The uk retailers have to cope in addition with the arrival on the market of the american giant Amazon, which has acquired the organic food store Whole Foods, as well as with the growth of online sales, as evidenced by the good health of the specialist british Ocado. "If we feel that customers are absolutely supportive of what we're doing then yes of course we have optionality going forward", he said.
Shares in Tesco were up 0.5 percent at 1515 GMT.
The latest figures by Kantar Worldpanel, for the three months to 9 September found that Aldi and Lidl had grown their respective market shares to 7.6 per cent and 5.5 per cent respectively, while Tesco remains the biggest player with 27.4 per cent.
"The intention is for us to be cheapest in town", Lewis said.
Products grown or manufactured in the United Kingdom are set to make up 80 per cent of all items sold, the firm said, while 1,800 of the 2,600 brands will be under Jack's own label.More news: Labour MP David Lammy Tears Into Theresa May After Brexit Statement
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"Jack's fits perfectly into the current consumer zeitgeist and will drive revenues as well as protecting margins across the Tesco group", said Freddie Lait, chief investment officer of Latitude Investment Management. A large chicken is priced at 3.19 pounds, while four pints of semi skimmed milk will cost 1.09 pounds.
Between 10 and 15 stores are planned for new locations, next to existing Tesco stores, and a small number of converted Tesco stores.
He said: "Jack's will need to work hard to dent the success of Aldi and Lidl, and will also need to prove its value against the wider Tesco offering including its existing chain of One Stop convenience stores".
Tesco is stepping up its fightback against Aldi and Lidl with the launch on Wednesday of its own cut-price chain, Jack's.
"The staff in the new stores are on different terms and conditions to other Tesco staff, which involves a higher hourly rate but fewer other employment benefits".
Pressed on whether he was concerned about Jack's cannibalising Tesco's business, the CEO said that he would sooner the business cannibalise itself, than let someone else do it.