What happens when your slogan is ‘Probably the best beer in the world’, but UK beer drinkers are telling you that it’s probably not?

That’s the reality Carlsberg was faced with last year. As it bravely said, “We lost our way. We focused on brewing quantity, not quality; we became one of the cheapest, not the best.” And to further underline this, Carlsberg had lost 1.6million drinkers over the last 5 years.

There was only one thing for it, Carlsberg needed to get back to its roots and focus firmly on the art of brewing once more.

First, its famous lager was completely re-brewed from scratch, to appeal to a new generation of beer drinkers. Then the marketing campaign was thoroughly re- thought; a bold strategy was employed, which turned the brand’s perceived weakness into something more positive.

Starting in social, guerrilla marketing tactics were employed on Twitter, tackling the negative perceptions of Carlsberg head-on in disruptive and entertaining ways, promoting some of the harshest comments posted about the beer over the last few years.

Some of these “Mean Tweets”, were turned into content films, where the nastiest tweets were read aloud by Carlsberg employees.

In OOH and print, the iconic line “Probably the best beer in the world” was subverted, to read “Probably not....”, in order to inform the public that Carlsberg were aware of the shortcomings of its old beer, and created a great new Danish Pilsner to replace it.

Finally, the campaign culminated with the return of Carlsberg’s brand philosopher Mads Mikkelsen. Mads introduced the new beer - while hinting at murderous retribution for the man “responsible for the old brew”.

This brave and highly risky strategy has paid off. Since the campaign launched, Carlsberg UK has seen a 15% increase in quality perceptions; 23% increase in recommendation, a 20% increase in off–trade shoppers, and a 14% increase in the on-trade rate-of-sale.

The Mean Tweets films not only reached 9.85 million Twitter users, but they piqued the curiosity of those who didn’t traditionally drink Carlsberg. So much so, that they tried the new brew, then tweeted how much they loved it.

As they say, the best advertising is word-of-mouth.