The battle of the Christmas adverts: what's the magic formula?

It's that time of year again - it might still be November but retail giants including John Lewis, Sainsburys, M&S and Iceland have already unveiled their Christmas adverts.

So what's the secret to the perfect festive marketing campaign?

First and foremost, a strong, emotional story makes a intoxicating ingredient for many Christmas adverts, says Elias Jahshan, editor of Retail Gazette.

This continues to be a common theme with John Lewis and Sainsburys both opting for heart-warming stories this year.

John Lewis have drafted in Sir Elton John, with their advert tracing the pop star's musical career in reverse - right back to the day he got his first piano as a young boy.

As the story unfolds, the singer's enduring hit single Your Song plays in the background. (That also completes a bit of a musical circle as Ellie Goulding recorded a version of Your Song for the 2010 John Lewis Christmas ad).

Meanwhile the Sainsbury's advert depicts a school Christmas show, following an eight-year-old girl who overcomes her nerves to deliver a knock-out performance.

While it's not always immediately obvious how these adverts promote products, retail expert Clare Bailey argues an emotional connection can still drive brand loyalty.

However, it's not the only tactic, as some retailers are less reticent about putting their products front and centre of their advertising campaigns - and Mr Jahshan argues traditional sales techniques can still be effective if done well.

Waitrose's "Too good to wait" festive advert for 2018 shows a couple abandoning their kiss under the mistletoe to rush to a table laden with food items available from the store. And Marks & Spencer squeezes in a dizzying amount of products in its "Must Have" advert starring Holly Willoughby and David Gandy.

Ms Bailey says: "If you look at the adverts from people like Marks & Spencer and Waitrose they're talking product, product, product.

"It's like 'hey our Brussels sprouts are better than Aldi's'. Whereas John Lewis is saying we're just nice people and we want to make you feel good."

Mr Jahshan says recruiting a big name can also create a feeling of excitement, calling the recruitment of Sir Elton is "a huge win" for John Lewis.

"It not only appeals to John Lewis' core consumer demographic, but it's also a clever marketing tactic given the #EltonJohnLewis hashtag the advert has now created," he says.

The BBC's arts editor and critic Will Gompertz agrees the "national treasure" is a smart choice and "the embodiment of the retailer's values".

But Ellen Hammett, who covers retail for Marketing Week, points out that this approach could backfire.

"The concern is that it will be remembered as 'that Elton John ad' rather than being associated with John Lewis. Elton might see a spike in album sales though," she says.

It hasn't escaped notice that the pop star has a retirement tour scheduled for next year, while a film about his life, Rocketman, is also set to be released in 2019.

One advert that you won't be seeing on TV any time soon is Iceland's, which highlights the impact of palm oil on rainforests through the story of an orangutan whose home is destroyed.

Clearcast, the body that approves TV ads, said it wasn't approved because the film was made by environmental organisation Greenpeace and so breached political advertising rules.

But Ms Hammet says the advert has still been hugely successful after going viral on social media.

"It's generated a huge amount of praise for a retailer that would otherwise probably have struggled to gain cut-through during the Christmas period," she says.

However Mr Jahshan warns that if brands are going to get political in their adverts they need to back it up with action or risk being branded opportunistic.

For example Iceland has committed to remove palm oil from all its own-brand products by the end of this year.

You could be forgiven for missing the Christmas message in Iceland's ad - it doesn't have a particularly festive theme.

But does that matter?

"I think people want Christmas ads to feel at least a little bit festive. That's what's going to get them in that all important 'feel good' Christmas mood," Ms Hammet says.

However she says Iceland's advert seems to be aiming to build support for the brand in the long-term rather than just over the festive period.

John Lewis's advert has also faced criticism on social media for being more about Elton John's life than the Christmas spirit.

But Will Gompertz says it still has enough festive charm to warm the hearts of the public.

"We learn that a piano is for life, not just Christmas - and music can change lives," he says.

"Not a bad message for Christmas."