One of Britain’s most beloved birthday party staples, Colin the Caterpillar, has found himself in the middle of a legal dispute, as Marks & Spencer (M&S) has filed a lawsuit against German discounter Aldi, claiming trademark infringement. The supermarket giant alleges Aldi’s Cuthbert the Caterpillar cake mimics its iconic Colin product too closely, potentially misleading customers.

M&S argues that Cuthbert is “riding on the coat-tails” of its long-established reputation for quality and freshness, and could confuse shoppers into believing the two cakes are comparable in taste and standard. The retailer has owned trademarks related to the name, packaging and appearance of Colin the Caterpillar since the cake’s debut in 1990.

A British icon with a sweet legacy

Colin the Caterpillar has been a fixture of birthday celebrations in the UK for over three decades. Since its launch, more than 15 million Colin cakes have been sold. The character has grown into a family of confections, including Connie the Caterpillar, mini-Colin cupcakes, and themed seasonal editions.

M&S has also aligned the cake with charitable causes, notably releasing a Macmillan edition Colin for the Macmillan Coffee Morning campaign, featuring green sprinkles and purple feet, with 10% of sales going to Macmillan Cancer Support.

In a statement, an M&S spokesperson said: “We know the M&S brand is special to our customers and they expect only the very best from us. We want to protect Colin, Connie and our reputation for freshness, quality, innovation and value.”

The caterpillar cake competition

The caterpillar cake has become a staple for British retailers, with several supermarket chains introducing their own versions. These include Cecil from Waitrose, Morris from Morrisons, Clyde from Asda, and Aldi’s Cuthbert—each priced between £5 and £7.

While many of these cakes bear visual similarities to the M&S original, M&S has chosen to target Aldi specifically, arguing that Cuthbert’s similarities go beyond inspiration and into brand infringement.

Colin v. Cuthbert: A case to watch

The legal case between M&S and Aldi has sparked public curiosity—and amusement—on social media, with many Britons weighing in on their favourite caterpillar cake. Others are watching closely to see whether the case will set a precedent in brand protection, particularly when it comes to novelty food products.

As the dispute unfolds, it’s not just Colin and Cuthbert with something at stake—Cecil, Morris, Clyde, and their respective creators may also be paying close attention to the outcome of what’s becoming a rather serious slice of the cake world.