CANNES: Nestlé, the world's biggest food manufacturer, has taken the Grand Prix in the Media category at the Cannes Lions International Advertising Festival, for a campaign promoting its Kit Kat brand in Japan.

JWT Japan was the agency responsible for producing the winning strategy, which was based on the translation of the words "Kit Kat" into Japanese – Kitto Katso means "surely win."

The agency combined this idea with the national custom of sending students good luck cards before they take exams, and forged a tie-up with the country's postal service to establish "Kit Kat Mail".

As a result, it produced edible "postcards" that were sold in 20,000 post offices across Japan, which could be mailed on to students, and then eaten once the recipient had finished reading the message.

Nick Brien, president/ceo of Mediabrands Worldwide, and head of the media jury, said: "It was a brilliant idea, flawless execution and amazing results. They created a business model that didn't exist before."

Not only did Kit Kat Mail generate $11 million (€7.8m; £6.7m) worth of free PR, but it also established the brand in a new retail market and, as a final mark of success, Nestlé has decided to keep selling the product.

A total of 20 Golds, 29 Silvers and 69 Bronzes were awarded in the media category, with Nissan, Toyota and Mars among the other big winners.

Virgin Atlantic, the airline, took the Grand Prix in the Radio competition, for a campaign developed by Network BBDO Johannesburg called Plain Insanity, which advertised the "amazing" prices available to travel first class from the country to London.

In the ads – entitled "Dancer", "Ferret" and "God" – a traveller meets a number of other passengers who have received such good deals to fly first class that the voiceover argues that they must be "insane" to make such claims.

Only one advertiser took Gold in the radio category – the National Thoroughbred Racing Association in the US – with two companies receiving Silvers, and a further 11 taking Bronzes.

In the Outdoor section, a campaign for The Zimbabwean newspaper to raise awareness of the plight of the country under Robert Mugabe – devised by TBWA/Hunt/Lascaris/Johannesburg – received the Grand Prix.

Billboards were printed on bank notes from Zimbabwe, which have lost all value as a result of massive inflation, and carried taglines such as "Thanks to Mugabe this money is wallpaper" and "It's cheaper to print this on money than on paper."

The news title is sold in South Africa and the UK, which both have large expatriate communities, but is subject to a "luxury import" tax of 55% in its home country.

A total of 69 Lions were awarded in the Outdoor competition, including 11 Golds, 21 Silvers and 36 Bronzes.

Data sourced from Media Guardian/AdAge; additional content by WARC staff