McDonald’s no longer has the exclusive right to use the label “Big Mac” in reference to chicken burgers sold in the European Union after a ruling by the EU’s highest court.

The American fast-food chain popularised the nickname for large burger sandwiches, registering it as a trademark in the EU in 1996.

But following a legal challenge from Supermac’s, a rival chain in Ireland, other companies will now be free to use the name “Mac” to sell poultry products or in their chains’ names.

The European Court of Justice found that McDonald’s could not show it had made genuine use of the trademark for a continuous period of five years.

“McDonald’s loses the EU trade mark ‘Big Mac’ in respect of poultry products,” the judges ruled.

McDonald’s noted in a statement that the court’s decision did not affect its right to use the “Big Mac” trademark.

But it does open the door for other chains to use the name, including Supermac, the firm that brought the challenge.

Supermac, founded in 1978 in Galway, sells beef and chicken burgers and chicken nuggets at 120 red and white branded outlets across Ireland.

It has been embroiled in a seven-year legal battle with the US chain over the right to use brand terms including “Mac”.

Supermac’s managing director, Pat McDonagh, said the ruling displayed a “common-sense approach to the use of trademarks by large multinationals”.

Supermac’s accuses McDonald’s of “bullying” smaller firms through the defence of its trademarks, aiming to stifle competition.

The dispute goes back to 2017 when McDonald’s blocked Mr McDonagh from registering Supermac’s as a trademark, to pave the way for expansion outside Ireland.

Mr McDonagh countered that McDonald’s was not using its trademark for restaurants, so other firms should not be blocked from using the term “Mac” in their names.

“We knew when we took on this battle that it was a David versus Goliath scenario,” Mr McDonagh said.

“We wholeheartedly welcome this judgement as a vindication of small businesses everywhere that stand up to powerful global entities.”

McDonald’s 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.”

The chain did not say whether it planned to appeal against the decision.

The ECJ’s ruling revokes McDonald’s trademark for restaurants and for poultry products, retaining it only in reference to the red-meat burgers it originally referred to.

Supermac’s remains in dispute with McDonald’s over the trademark in the UK, since post-Brexit EU trademark law no longer applies in the UK.