Lidl, Aldi and Netto are in prime position to exploit any drop in disposable incomes or insecurity about the country's economic future, say market analysts.
The hard discounters' share of the overall grocery market would rise 1.7 percentage points to 6.7% in the next two to three years as shoppers tighten their belts, predicted HIM.
It said the number of UK shoppers using discounters at least once a week had increased by almost 40% since 2004 to 4.4 million, or 11% of the UK adult population.
That figure was expected to rise as ambitious growth plans harboured by Aldi, Lidl and Netto came to fruition. Falling disposable income, caused by rising interest rates and inflation, would help discounters attract new customers, according to Tom Fender, sales and marketing director at HIM.
"People still need to eat and drink, but more people will go for standard products rather than luxury ranges," he said.
Internal investment was helping to improve customer perception, he added.
"The discounters are not just maintaining a strong price position, they are also improving the shopping environment. They are investing in presentation and fresh produce and greatly improving the ambience in-store," he said.
Trends indicated a growing middle class customer base was initially attracted to stores by non-grocery offers but then found the food appealed to them too.