Two of the country's leading supermarkets are embroiled in a dispute over the name of their discount ranges.
Waitrose bosses have sent a legal letter to Asda after it announced it is renaming its budget Smart Price line "Just Essentials", which Waitrose says is too similar to its Essential Waitrose brand.
"We were surprised to hear that Asda is launching an essentials range as the Essential Waitrose brand has been in use since 2009 and has built up a strong reputation for value, quality and higher welfare standards in that time," a Waitrose spokesperson said.
"As we’ve also protected the name as a trade mark, we have raised this with Asda and are awaiting a response."
Asda insisted the term is commonplace.
"The word ‘essentials’ is a generic and commonly used term by retailers to describe their value product ranges," a spokesperson said.
Asda said the rebrand will hits stores in May and will be expanded across its 581 locations this summer.
It announced the name change alongside news it is increasing the size of its lower-cost range from 200 to 300 items.
Waitrose, which is owned by the John Lewis Partnership, stocks around 1,000 items in its Essential line.
Asda came under fire from food poverty campaigner Jack Monroe last month for price increases and a lack of availability of its lower price range.
In response to her campaign, Asda said it would stock its Smart Price and Farm Stores ranges in all its stores and online by March 1, to help its customers with the cost-of-living crisis.
Mohsin Issa, Asda’s billionaire co-owner, said this week: "We understand that customers are increasingly worried about the cost of living and want help to keep their grocery bills in check, whilst still being able to buy healthy and nutritious food for their families.
"Our new ‘Just Essentials’ range has been specifically designed with this in mind, combining our lowest prices with a much larger and more diverse range of great value products to meet all household needs."
The shake-up of its product range came as Asda revealed revenues of £20.4 billion in 2021, representing a 0.6% increase in like-for-like sales, excluding fuel.
It comes a week after the Office for National Statistics said inflation jumped to a 30-year-high of 6.2% in February, with food inflation at 5.3%.