As if supermarkets weren't suffering enough with the threat of discounters, a new spectre is rearing its head - Amazon Fresh.
Stealthily launched in London and Birmingham under the Amazon Prime Now banner, kitchen essentials like milk will be delivered to people's door within the hour.
Analysts have already warned that Amazon will have an impact on the sector, but just how worried should they be?
We pitted middle England's favourite, Ocado, against Amazon in a simple test comparing prices for a selected basket of goods to get an idea - here's how they compare.
Amazon trumped Ocado on price for the majority of items, and the total bill came in 20 per cent cheaper.
We didn't include offers such as buy one, get one free, and used branded products that were exactly the same size ot weight. We also didn't include delivery charges in the comparison, which can vary with each retailer.
The shopping basket is by no means representative. With Prime still in its infancy as Amazon test out its logistics, everyday items such as eggs, bacon and bananas are not available (yet), while Heinz ketchup comes only in a bulk buy of 10 (good for ketchup lovers though).
With price the major factor for consumers when doing their shopping (hence the rise of Aldi and Lidl), and the promise of delivery within the hour, Amazon Fresh could just leave Ocado in the dust.