The indulgence of the Christmas season approaches, but an air of potential gloom hangs over this year's big food and retail advertising campaigns. Maybe for the last time retailers and brand owners are spending the countdown to Christmas investing heavily in marketing to swell sales and fatten up their market share.

Underlying the jolly images of tinsel and holly is a troubling issue. The spectre of heavy-handed regulation haunts the Christmas feast.

Keen to further tackle the obesity crisis, the government has expressed particular concern over the advertising of high fat, salt and sugar (HFSS) foods to children. In February Ofcom introduced new rules to control the volume and content of food and drink TV advertising to children. And two months later, the Committee of Advertising Practice brought in new rules for the content of non-broadcast advertising that prevents the use of celebrities and licensed characters, promotional offers and health and nutrition claims in food and drink ads targeted at under-12s.

In some quarters, though, these restrictions do not go far enough. There have been calls for a 9pm watershed for all HFSS food ads on TV. Secretary of state for health Alan Johnson appeared to lend his support to these calls when he slammed brands earlier this year for exploiting a loophole by advertising in programmes such as The X-Factor, which appeal to adults and children.

Which? has been the most vociferous champion of a 9pm watershed for junk food ads. Last month it released research that found 12 of the 20 most-watched programmes by children under 10 are not covered by current rules.

"If a watershed ban on HFSS foods were imposed because of the FSA's Nutrient Profiling Model, products such as cheese, raisins, Marmite and low-fat margarine would be banned from advertising before 9pm," says Baroness Peta Buscombe, chief executive of the Advertising Association. "It would be far better if government worked with the industry to find positive, effective solutions to obesity."

The government's stance on a watershed is unclear. In fact, a marketing trade magazine slammed the Department of Health for 'schizophrenic messages'. However, a recent letter from health minister Dawn Primarolo to the Advertising Association suggests the government remains keen to work with the industry, raising hopes that a watershed will not be imposed.

Tesco's current campaign shows how future Christmas ads may look, focusing on its wide-ranging gift offering. But one fears for the likes of M&S, which would be banned under possible proposals from advertising its famous chocolate pud.

While the picture is far from clear, it is possible this Christmas may be the last hurrah for blockbuster campaigns. However, some agency executives are trying to pre-empt any calls by monitoring their own output more carefully. "Advertisers are becoming more circumspect about when and how they advertise food," says Neil Henderson, managing partner of St Luke's, whose clients include Divine Chocolate.

At JWT, the agency behind Quality Street's Christmas campaign , the sentiment is that a 9pm watershed is unjustified and would strip millions of pounds in revenue away from TV, adversely affecting programme quality. The agency's professional development director Kate Bruges, who represents JWT on the Advertising Association's Food Advertising Unit, says attitudes have changed and that today's food advertising is not designed to go "in the back door" and appeal to children watching mainstream programmes.

However, ahead of any changes to regulation, the campaigns we will see in the run-up to Christmas will rely on tried-and-tested tricks such as using celebrities. Brands will also do what they can within current regulation to win the most desirable slots on TV . Celebrity endorsement figures loom large once again among the retailers, with faces such as Jamie Oliver, Julie Walters, Kerry Katona, Lulu and the Spice Girls coming to the fore .

Mars has spent £1m on advertising Galaxy Mistletoe Kisses, while Coca-Cola has brought back its Holidays Are Coming TV ad thanks to popular demand, claiming shoppers say the ad is part of Christmas. Coke has a long association with Christmas - it helped define the modern iconography of Santa by commissioning artist Haddon Sundblom to create an image for its advertising in 1931.

For this feature, we asked leading advertising executives Russ Lidstone of Euro RSCG and Andrew McGuinness of Beattie McGuinness Bungay to separate the crackers from the turkeys.

Hopes for the new year, meanwhile? That advertisers have already done enough to avoid a draconian clampdown - and that Gordon Brown doesn't have a large appetite for playing politics with chocs and sprouts. n

What Christmas ads have we left out of our list? Send us your favourite seasonal campaign: email 10/10

The campaign: Actually, campaigns - Coca-Cola has revived two classics. Holidays are Coming features a convoy of illuminated red Coca-Cola lorries snaking its way through a wintry landscape. And The Greatest Gift features Santa bestowing bottles of Coke on a grateful woman at various points in her life. At the end of the commercial, the woman, who now has a child of her own, returns the favour by handing a bottle of the soft drink to an appreciative Santa. The ad uses the strapline 'The Coke side of Life'.

RL's verdict: The art director of the modern Christmas is running two executions that unashamedly celebrate the spirit of Christmas and the role Coke plays at that time of year. In my view, there is good schmaltz and bad schmaltz and the lorry execution in particular is brilliant schmaltz. The advert still makes the hairs on my neck stand up through unbridled romanticism and anticipation. Only Coca-Cola does schmaltz this well.Tesco 9/10

The campaign: They'll show you what you want, what you really really want. Unbeknown to one another, the Spice Girls are buying gifts for each other in the same store, and each one narrowly avoids being discovered thanks to the convenient disguise provided by strategic placement of Tesco's biggest-ever range of toys and gifts.

AM's verdict: I am partial to ham at Christmas but I'm not sure about this variety. Fun and memorable but totally disconnected from the rest of Tesco's activity. But maybe that's the point. Either way, a very expensive tactical advert for gifting.Sainsbury's 9/10

The campaign: Fancy a glass of Taste the Difference vintage Cava with fresh pomegranate juice? Jamie Oliver suggests you should. The celebrity chef proposes lots of mouthwatering food and drink combinations as he is transported from his kitchen to a winter wonderland populated by industrious little people in extravagant costumes. 'Try Something New Today' is the message.

AM's verdict: Another supermarket, another celeb, but it's the best of the batch. It builds on the brand's positioning, uses its icon Oliver and sells Christmas lines. It entertains and informs. Iceland 8/10

The campaign: Party like a celeb with Iceland, urges the voiceover, bringing a festive dimension to its sponsorship of ITV's I'm a Celebrity Get Me Out of Here. Ads feature past I'm a Celeb contestants Kerry Katona and Jason Donovan. "You can take the man out of the jungle..." shrugs Katona as Donovan spears a prawn from the buffet table at a swanky party. It's pure cheese.

RL's verdict: Iceland tries to show the relevance of its sponsorship and link it with Christmas in 10 seconds. But the poor performances by Katona and Donovan leave a terrible taste in the mouth.Quality Street 7/10

The campaign: Quality Street positions itself as the essential Christmas treat. To the Christmas carol Good King Wenceslas, the ad features t he brand's shiny wrappers morphing into shapes such as a wreath and a Christmas tree. The Nestlé brand's distinctive tin is shown at the climax with the strapline 'Quality Street makes Christmas'.

RL's verdict: Quality Street has a warm place in our hearts at Christmas and this execution celebrates it . Nicely executed and a change of direction, but it lacks some warmth and people, which is the essence of Quality Street.Bernard Matthews 7/10

The campaign: Reprising the Never on a Sunday theme tune used for the brand's cooked meats commercial, the ad features strong branding and shots of a perfectly cooked Golden Norfolk Turkey with close-ups of the bird and its succulence. The lyrics highlight the versatility of turkey and the British origins of Golden Norfolk Turkey.

AM's verdict: Christmas has traditionally been a time when Bernard Matthews has been hated by turkeys but loved by shoppers. But after the past year shots of turkey and tinsel may not suffice to give Bernard a happy new year.Morrisons 7/10

The campaign: "Do you know what I'm dreaming of?" asks Lulu, pushing her trolley to Take That's Shine, aided by celebrities such as Diarmuid Gavin , Denise van Outen and Alan Hansen enthusing over festive foods. The ad ends with the strapline 'Make it a fresh Christmas at Morrisons'.

RL's verdict: The Fresh campaign embraces the 'must-have' celebrity rule with Lulu and a who's who of B-list celebs. Espousing the joys of fresh food over Christmas is single-minded but the generic 'fresh' strategy isn't necessarily the best expression of Morrisons' truth. ASDA 7/10

The campaign: Shot in the mockumentary style, Asda has forsaken Yuletide glitz in favour of down-to-earth banter. Actress Julie Walters appears as a trainee who makes wisecracks while talking to shoppers and staff. The strapline is 'There's no place like Asda this Christmas'.

RL's verdict: This campaign shows the breadth of the Asda range and continues to challenge perceptions that Asda is a faceless logistics machine. Walters presents Asda in a glowing light and avoids the Christmas hyperbole. But for an old romantic like me, it lacks some Christmas tingle.OXO Liquid Stock 6/10

The campaign: An ad with festive overtones as it focuses on family mealtimes. It cuts between three people preparing meals for their families to highlight the different flavours: chicken, beef, lamb and vegetable. The campaign supports the introduction of a concentrated liquid stock with the strapline 'The Oxo Family, it's grown'.

AM's verdict: This ad introduces us to the Oxo family of products in a clumsy way . It is not really a Christmas advert, more an ad that is on at Christmas. It's confusing on first viewing and unrewarding on the second.Anchor Butter 5/10

The campaign: Arla Foods' Anchor has forsaken TV and chosen women's and lifestyle press ads to promote Anchor's free-range strategy. Ads feature bright green grass blades with a clear, simple message: 'The butter your free-range turkey would choose.' In smaller text is the message 'Merry Christmas from the Free Range Butter Co'.

AM's verdict: I'm a fan of the new Lurpak work but Anchor fails to ignite my taste buds. The proposition - free-range turkeys would choose free-range butter - could have been exciting. Instead we get grass. Not foodie and not Christmassy. Our advertising experts

?"I'm a sucker for Christmas advertising. As a kid I looked forward to seeing a snow-filled Woolies on TV crammed full of Yuletide clichés. This year, while Woolies has replaced its b-list listers with the cuddly 'Wool' and 'Worth' puppets (surely they began as a joke in a meeting that has now gone too far), there's a plethora of what the Americans might call sub-prime celebs on display. Add a sprinkle of Dickensian Britain and you have the recipe for this year's Christmas ad offering"

Andrew McGuinness partner, Beattie McGuinness Bungay. Clients include Wall's, McCain, Diageo, Carling and Pretty Polly

?"Christmas is perhaps the only occasion in the year when ordinary people talk about and sometimes even look forward to the adverts. When Coke Christmas ads are on TV, Christmas has officially begun. The challenge these days is how to break out of 'name appendage celebrity inflation' (I'll see your Alan Hansen and raise you the Spice Girls). A competitive, relevant and true take on Christmas is hard to find but John Lewis' 2007 TV campaign is a great example - blending relevance, information and anticipation in a compelling Christmassy way. It scores 10/10 on the Lidstone Christmas Tingleometer."

Russ Lidstone chief strategy officer, Euro RSCG London. Clients include Reckitt Benckiser and Alberto Culver