This week, National Statistics released new figures revealing that household spending on food and drink products consumed outside the home had more than doubled to £87.5bn from 1992 to 2004.

During the same period, spending on fresh and processed food and drink products grew at half the rate to £85.8bn.

It doesn't take a rocket scientist to work out that there's a huge opportunity in the foodservice arena. But are supermarkets exploiting it?

There has certainly been a flurry of activity as supermarkets scramble to offer something a bit more sophisticated than the sausage, beans and chips café of old.

Witness Whole Foods Market's announcement that it plans to open three restaurants in its Kensington flagship store next spring; Spar Ireland's pioneering format of juice bar, coffee concession and New York-style deli counter; and Northern supermarket Booths' Artisan restaurants, boasting a menu of speciality foods grown in the local area.

Marks and Spencer now offers shoppers three types of foodservice in-store including Café Revive, now the third-largest coffee shop chain in the UK.

The retailer is trialling an eat-over deli in four stores, serving a range of snack foods such as Parma ham and olives, but at present has no plans to roll it out. It is also opening its first full service restaurant in Newcastle in October, which will serve dishes such as steak and chips. "The idea is that you can have a relaxing meal and stay for a long time," said a spokeswoman. "We're looking at ways to bring our food to a wider audience."

Jeffrey Young, managing director of the consultancy Allegra Strategies, says: "Eating in store rounds off the experience. Supermarkets will be able to unlock spend by providing a modern dining experience.

"They will get income from the rental space that, say, Costa Coffee is using in its outlets. It also extends the time people are in-store and gives them the chance to have a break before continuing to shop.

"It provides an opportunity to add value to products, which is what has been done for the coffee sector. It moved from £1 a cup served in polystyrene cups to a brand new experience in quality cardboard cups for £2 to £3 a shot. It's about adding value to the product and gaining additional spend."

But Young believes there are dangers in being too ambitious. "In most stores you're not going to get the full service restaurant with white linen table cloths," he says.

"You have to look at the demographic profile of your consumers. Tesco and Asda will be more mainstream than, say, M&S or Waitrose. "You may get older people and more traditional shoppers who don't want the rocket with balsamic vinegar sort of meal.

"They may just want the fish and chips that they are used to having. There's the danger of getting too far ahead of yourself."

Julia Hatcher, category manager of foodservice at Sainsbury's, agrees. "The key to any in-store foodservice strategy is to have formats aligned to a store's size, location, demographic and customer shopping habits," she says.

"One size does not fit all and our aim is to expand our current portfolio to pull the 'to go' and 'eat in' journey closer together.

"Our customer restaurants are completely self-serve or have a serveover coffee bar attached. The coffee bars model any high-street offer and have the flexibility to be with or without seating."

But Julie Starck, IGD analyst, believes that shoppers will increasingly expect an element of luxury. "The consumer presents many challenges to retailers providing foodservice in-store," she says. "IGD research indicates that 34% of shoppers see the environment of a café as important, so just adding an area next to the main part of the store may not work as well as something that is more removed.

"Consumers go to cafés or out to lunch to be waited on," Starck adds. "A quarter of people say service is important. Having to press a button for cappuccino is never going to capture the theatricality of the fresh coffee experience."

With supermarkets investing money and precious floorspace to cafés and restaurants, is the eating out experience here to stay?

"I think so," Young says. "People are more mobile - they want to eat when they're hungry rather than having set mealtimes.

"Foodservice in supermarkets is another bolt-on to what these supermarkets offer. It's about the whole experience, of which this is just another part."