Multiple retailers are set for a fresh assault on non food, as the range on offer meant out-of-town hypermarkets were now "destination stores in their own right for non-food goods".

With sales in out-of-town megastores (up 6.4%) outperforming both high-street outlets (up 3.9%) and convenience formats (up 5.1%), Nielsen research also revealed this was being driven by non-food sales, which grew by 8% over Christmas and 7.8% in 2007 as a whole.

The fastest-growing non-food sales came from mobile phones, games consoles, stationery and jewellery, Nielsen research showed.

And speaking at The Grocer's Non-Food in Grocery conference this week, OC&C Strategy Consultants associate director Anita Balchandani said the multiples now had a £77bn market to target as consumers lose their inhibitions about buying non- food products from supermarkets.

The £20bn retail market comprised of specialist shops for health & beauty, petcare and music were already 'gone', as the supermarkets muscled into their territory, she argued.

Now, she added, the supermarkets were figuring out how to increase sales in a market nearly four times that amount, with homewares, childrenswear, books and games consoles all considered to be 'going'.

"Grocers now account for 9% of total non-food sales, having already eroded the role of the specialist in some categories," said Balchandani.

"The next wave of growth is coming. We expect them to choose their categories very carefully and retailers in these areas are likely to face intense competition over the next three to five years."

However, all was not lost for the specialists, she added. She highlighted a range of "weapons" that non-food specialists in North America and France had used in their battle against Wal-Mart and Carrefour, respectively.

These included holding in-store events such as book signings, delivering exclusivity through own label and targeting categories under-served by the hypermarkets.

Categories with more breathing space included sports equipment, DIY and white goods, all of which were not currently priorities for supermarket chains, she added.

Mike Watkins, senior manager of retailer services at market research agency Nielsen, revealed the progress that multiples had made in attracting non-food custom.

Five years ago, fewer than one in three of Tesco's customers left with non-food products in their shopping baskets, he said, but in the week that Tesco announced plans to open high-street, non-food department stores, 67% now did so.

"Out-of-town supermarkets are becoming destination stores for non food items in their own right," said Watkins, adding that non-food sales contributed to the growth in market share of the big four.