The proportion of Britons who avoid the supermarket altogether in favour of online grocery shopping has doubled in recent years, figures show.
As many as 14% do all their grocery shopping online, up from 7% in 2014, analysts Mintel found.
Overall, 48% of consumers do at least some grocery shopping online, up from 43% in 2014.
Mintel is forecasting the market will grow by 12% this year after sales in the sector rose by about 15% last year, while total food retail sales grew by just 1.5%.
The growth comes as an increasing number of shoppers are opting to avoid a trip to the supermarket, with almost one in three online shoppers (29%) saying that in the past 12 months they have done more of their grocery shopping through the internet.
Nick Carroll, senior retail analyst at Mintel, said: "Online grocery is the quickest growing grocery channel.
"The fact that younger consumers are far more likely to shop online highlights that rising smartphone ownership and internet connectivity has created an expectation from consumers that they can get what they want, whenever they want it."
Three in five (60%) of those who shop online for groceries say they would be happy to purchase a full weekly shop online from discounters, Mintel found.
Mr Carroll said: "When it comes to the discounters, they have been a disruptive force in the UK grocery market, but this has been limited to physical retail to date.
"Our research shows there will certainly be a market for the discounters if they decide to take the plunge into online retailing."