Born from social listening, The Mayo McHack is a PR campaign at its core. McDonald’s not providing mayonnaise at their UK restaurants has been widely debated on social media for years, but instead of joining the debate, we decided to solve the issue.

We launched a hack that made it possible for people to order mayonnaise at every single one of the 1270 McDonald’s restaurants in the UK.

By launching the Mayo McHack, we tapped into an ongoing conversation, and finally served up the answer to a need that for years has been unfulfilled.

Hellmann’s is the number one mayonnaise brand in the UK and has always championed the cause of mayo lovers. As market leaders, they go the extra mile to ensure that mayo lovers can enjoy their favourite condiment wherever they desire.

And while mayonnaise is the most popular condiment in the UK, the major fries seller in the country, McDonald’s, does not offer mayo as a dip. Despite mayo's immense popularity, McDonald’s claims that "there's not enough demand for it."

In a bid to support the rights of mayo lovers, we decided to take a stand against this injustice, and set out to right this wrong.

Though McDonald’s doesn’t serve mayonnaise as a dip, they do serve hundreds of other items. Among them we found The Mayo Chicken burger, which includes… Mayo. In all McDonald’s restaurants and the McDonald’s app, you can customise your Mayo Chicken burger and remove ingredients until there's only one left - mayonnaise.

With this find, we launched The Mayo McHack - a hack that finally gave the UK their well deserved mayonnaise with their fries at McDonald’s. We launched the hack with an integrated campaign and encouraged people to customize their Mayo Chicken burger by de-selecting the chicken, the lettuce and the bun - leaving them with just the mayo. Mayo McHack finally made McDonald’s serve mayonnaise, and people who posted a photo of their hack were compensated for the £1.19 cost of the burger by Hellmann’s.

McDonald’s decision to not offer mayo as a dip has left mayo lovers all over the UK feeling disappointed. It's a subject that has been hotly debated in news articles and social media for years.

When McDonald's failed to listen to the demands of their customers, we knew we had to take matters into our own hands. Our strategy was to keep championing the mayo lovers of the UK, but this time serve up a solution for the problem.

By leveraging one of McDonald’s flagship burgers and asking people to turn it into mayonnaise, we turned every McDonald's order screen in the UK into vessels for our campaign.

Taking on a french fries giant in the name of mayo lovers, we didn’t just get McDonald’s to serve mayonnaise to their customers - we got them to serve our message as well; Mayo and fries is the happiest meal of all.

Every single execution of the Mayo McHack campaign guided mayo fans on how to “hack” McDonald’s to serve mayonnaise.

The hack itself, performed on any of McDonald’s 1270 ordering screens by removing ingredients from the Mayo Chicken burger until there was only mayonnaise left.

To support further, we promoted the hack on DOOH screens outside of McDonald’s restaurants, in print ads in regional newspapers, and on Hellmann’s own social channels.

We also reached out to the hundreds of people on social media who previously had asked McDonald’s to add mayo as a dip, telling them we had come up with a hack to serve them mayo.

To maximise social engagement, we also collaborated with 5 foodie influencers who created their own instruction videos.

People who performed the Mayo McHack and uploaded it on social media were compensated for the cost of the Mayo Chicken burger by Hellmann’s.

Apart from articles in news and trade press, Mayo McHack is one of Hellmann’s UK’s most successful social campaign ever, with an increase of social impressions of + 842% and an increase of engagement of +320%.

Hellmann’s brand consideration was up +46% and purchase intent was impacted significantly with a rise of +9pts and 72% agree that McDonald’s should serve Hellmann’s mayonnaise.

And while some people might see the issue as a small one, the UK didn’t, as the campaign had an increase of +5pts of the UK agreeing Hellmann’s is trying hard to have a positive impact on society. But then again, mayo with your fries is a serious matter. And, two weeks after our campaign ended, McDonald’s launched a limited edition mayonnaise.

On the negative side, McDonald’s weren’t loving it, which resulted in one (1) cease and desist letter from their lawyers.

The Mayo McHack campaign was born from the fact that Brits, although they’re one of the most mayonnaise loving people in the world, are denied the condiment at the biggest fries seller of the nation. When we realised that though McDonald’s doesn’t serve mayo as a dip, they do serve it in something else, we served up a hack to finally please every mayo fan in the UK. By siding with mayonnaise lovers and showing we always go further to have their back, Hellmann’s answered the cry for help and made McDonald’s serve mayonnaise and our message.