Who would have thought it? After years out in the cold, frozen food is undergoing a renaissance. Sales have risen a modest but significant 1.4% in the year to March [TNS] after several years in decline. The credit crunch and weakening economy have undoubtedly conspired to encourage shoppers to switch from pricier products to the more value-driven frozen category. But it would be naïve to think these were the only factors at play.

Over the past couple of years frozen food has benefited from big brand investment, a resurgent own-label industry and support from celebrity chefs - much of which has come in response to growing consumer demand for healthier foods.

The likes of Birds Eye and McCain have also started to reinforce the health message in their advertising. "Birds Eye's Truth campaign, and McCain's It's All Good advertising, have been talking about the goodness of frozen food, and their sales imply consumers have got the message," says Brian Young, director of the British Frozen Food Federation, adding that fish has been the star performer, with sales up 7.3% on last year according to TNS. "Birds Eye is branding its packaging with Omega-3 credentials and Young's Great Grimsby range of fish products boasts of its sustainable farming methods."

More effective branding has been key, agrees David Stokes, business manager at Nisa-Today's distribution arm. "Frozen food has always been a far better, fresher product than the chilled equivalent and consumers are now seeing it for themselves thanks to the past 12 to 18 months of excellent branded advertising," he says.

Celebrity endorsement has also played a part. Sales of Aunt Bessie's frozen mashed potato, for example, jumped 200% in the week Delia Smith championed the brand in her TV programme.

"There is a great deal of snobbery about frozen food but the industry has learnt much over the years," says Young. "Shoppers and chefs are liking what they taste."

They're also liking the fact that frozen food is less wasteful and therefore more cost-effective than chilled. "It cannot compete with frozen in terms of the wastage issue," says Young.

But perhaps the biggest reason for the resurgence of interest is the retailers, who, after years of neglecting the category, have finally woken up to its potential, improving availability and ditching the heavy promotions that were devaluing it.

"British retailers are a huge force behind the acceleration of frozen food," agrees Young. "The availability of products has improved, with the supply chain working better and improved in-store stock control. The multiples are more positive about frozen and have reduced the number of bogofs and special offers, which has improved the category's image. Premium products and fewer cheaper value items will keep values growing."

It's not just the big branded players that are benefiting. According to insiders, retailers are investing unprecedented amounts in the innovation and quality of their own-label products. They may even be investing more than in their chilled ranges, which would signal a remarkable reversal in fortunes for both categories. As cost pressures increase, frozen will continue to benefit at the expense of chilled, believes Young. "The heady days of double-digit growth in the chilled category are no more and the cards are now stacked in favour of frozen," he says.

Unfortunately, the shaky economy may have provided a less benign tipping point for chilled. n