Tesco is poised to unveil a voucher-at-till initiative to ratchet up price pressure on its rivals next week.

The Price Promise promotion will reimburse customers at the till if their shopping would have been cheaper at a rival retailer and, crucially, it compares both branded and own-brand products with Asda, Sainsbury’s and Morrisons. The voucher will be capped at £10.

Archrival Sainsbury’s compares the price of branded goods and gives shoppers the difference back through its Brand Match promotion, introduced 18 months ago. 

The new promotion, which will be introduced in stores in England, Scotland and Wales from March 11, has been trialled in Northern Ireland since last year. The retailer already has an online price comparison scheme. 

The initiative heralds Tesco’s biggest push on price since autumn 2011, when its Big Price Drop promotion was criticised for not engaging customers as effectively as rivals’ money-off vouchers. The promotion was followed by Tesco’s first profit warning in 20 years last January. 

The UK’s largest retailer is looking to fight back against rivals after Kantar Worldpanel data released last week showed Tesco’s sales fell 0.4% in the four weeks to February 17. Asda sales grew 5%, while Sainsbury’s grew 5.8% in the period.