The oat-drink, commonly referred to as ‘oat milk’, serves as a replacement for cow’s milk, whether poured on Weetabix or used to make a flat white, but cannot be called ‘milk’ officially, following the ruling this week in Dairy UK v Oatly AB [2026] UKSC 4.  

Oatly registered the trademark ‘Post milk generation’ in 2021, but was opposed by Dairy UK on the basis the registration was invalid since EU law, assimilated into UK law post-Brexit, prohibited the ‘designations’ of ‘milk’ and ‘milk products’ for any product other than those set out. There is also a proviso that this shall not apply ‘when the designations are clearly used to describe a characteristic quality of the product’.

The Intellectual Property Office declared the trademark invalid with respect to oat-based food and drink but allowed its use for T-shirts and other non-agricultural products. The High Court overturned this decision and the Court of Appeal then held registration of the trademark invalid.

Oatly appealed, questioning whether the use of ‘milk’ in ‘post milk generation’ is a ‘designation’. If so, Oatly argued the trademark was saved by the proviso as it clearly described a characteristic quality of the product.

However, five justices unanimously dismissed Oatly’s appeal, finding ‘post milk generation’ does use ‘milk’ as a ‘designation’ and it is not clearly being used to describe a characteristic quality. Therefore, the trademark is invalid when used in relation to food and drink.

Jim Dennis, partner at Simkins, said: ‘The Supreme Court has drawn a line in the sand by holding that, under UK law, “milk”, when used to describe a product, means milk secreted by a mammal unless the word is clearly used to describe a characteristic of that product.

‘In reaching that conclusion, the court closely followed retained EU law governing agricultural product names, leaving little room for creative branding. The judgment is a clear reminder to the plant-based dairy alternatives market to take great care in how products such as plant-based milk, cheese and yoghurt are described, so as not to fall foul of the regulations.

‘There is an exemption where the term is used to describe a characteristic quality of the product, for example coconut milk. The main difficulty for post milk generation was that it does not describe any characteristic quality of the goods at all, but instead it describes the consumer.

‘The judgment will pose a particular problem for Oatly, since part of their marketing strategy has been to compare their products favourably to, and at times disparage, dairy. The fact that Oatly took the case all the way to the Supreme Court shows how commercially important it is for the brand to position itself in this way. The ruling means that, in the UK at least, that approach will now have to be handled with far greater caution.’

Delivering their judgment, Lords Hodge, Briggs, Hamblen, Burrows and Stephens said ‘even if post milk generation were to be regarded as referring to the milk-free characteristic of the contested products, that characteristic is not being described “clearly”. In particular, does it mean that the product is entirely free of milk or only that the milk content is low? Take an analogous hypothetical trade mark, post alcohol generation. If that designated a drink, it would not clearly indicate whether the drink is merely low alcohol or has no alcohol’.

The justices said the trademark ‘plainly does make sense when used on a T-shirt. That is precisely because it is most obviously describing a type of young consumer who might proudly wear a T-shirt proclaiming that he or she is a member of the anti-milk post milk generation. But that has nothing to do with a characteristic quality of the T shirt’.