As Amazon takes on the UK grocery market, can it deliver a profit?

British supermarkets are nervous about the launch of Amazon Fresh. But it hasn't exactly set the US alight yet

After years of expectation, Amazon finally launched its Fresh grocery service in the UK last week, parking its tanks on the lawns of the country's biggest retailers. It promises "everything you need for your weekly shop", from artisanal Stilton to tangy cheese Doritos, delivered to your door in a cool box.

Some analysts are predicting the US online giant could grab up to 3% of the UK grocery market by 2020. That would represent 1.4bn of sales, much of which would be stolen from the already struggling traditional supermarkets - Tesco, Asda, Sainsbury's and Morrisons.