McDonald’s has lost its exclusive rights to the “Big Mac” trademark for some of its burgers in the European Union, after a court ruling.

The EU General Court has ruled in favour of Irish fast food rival Supermac’s in a long-running legal battle.

The court said McDonald’s failed to prove that it was genuinely using the Big Mac name over a five-year period for chicken burgers, poultry products or restaurants.

The Big Mac is a hamburger made of two beef patties, cheese, lettuce, onions, pickles and Big Mac sauce, according to the company’s website.

However, Wednesday’s decision is about more than burger names.

The dispute erupted after Galway-based Supermac’s started eyeing up European expansion plans and applied to register its company name in the EU. McDonald’s objected, saying consumers would be confused because it already trademarked the Big Mac name.

Supermac’s filed a 2017 request with the EU’s Intellectual Property Office to revoke McDonald’s Big Mac trademark registration, saying the US company couldn’t prove that it had used the name for certain categories over five years.

After the regulator partially approved Supermac’s request, McDonald’s appealed to the EU court.

“McDonald’s has not proved that the contested mark has been put to genuine use” in connection with chicken burgers, food made from poultry products or services associated with operating fast-food, drive-through or take-out restaurants, the court said, according to a press summary of its decision.

Supermac’s portrayed the decision as a David and Goliath-style victory for small business.

Managing director Pat McDonagh accused McDonald’s of “trademark bullying to stifle competition”.

“This is a significant ruling that takes a common-sense approach to the use of trademarks by large multinationals. It represents a significant victory for small businesses throughout the world,” managing director Pat McDonagh said.

The Irish company doesn’t sell a burger called the Big Mac but does have one called the Mighty Mac that has the same ingredients.

McDonald’s was unfazed by the ruling, which can be appealed to the European Court of Justice, the bloc’s highest court, but only on points of law.

“The decision by the EU General Court does not affect our right to use the ‘Big Mac’ trademark,” the company said.

“Our iconic Big Mac is loved by customers all across Europe, and we’re excited to continue to proudly serve local communities, as we have done for decades.”