Authored By: Arshiya Alji
Middlesex University Dubai
ABSTRACT
This article examines whether UK trademark law adequately protects single-colour marks in the luxury fashion industry, using the Christian Louboutin red sole as its central analytical lens. While colour can function as a powerful commercial identifier, the conditions for registration – particularly the requirement of acquired distinctiveness – impose evidentiary burdens that systematically advantage established luxury houses over emerging designers. This article argues that the post-Brexit conversion of Louboutin’s EU trademark into a domestic UK mark does not guarantee continued protection, and that the absence of an express functionality doctrine for colour creates further structural uncertainty. Comparative analysis of US and Japanese jurisprudence reveals that colour mark protection is neither universal nor settled. Three targeted reform recommendations are proposed.
KEYWORDS
Trademark Law, Colour Marks, Acquired Distinctiveness, Luxury Brand Protection, Post-Brexit Intellectual Property, Trade Marks Act 1994, Non-Traditional Marks
1. INTRODUCTION
It takes approximately three seconds for a consumer to recognise a Louboutin heel from across a room. It has taken over thirty years of litigation for the law to decide whether that recognition deserves protection.
Christian Louboutin convinced the courts that a single colour could belong to him. Since 1993, Louboutin has applied a specific shade of lacquered red – Pantone 18-1663 TP – to the outsoles of its high-heeled shoes. That red sole is worth billions. Its legal fate in the United Kingdom since Brexit, however, is far less settled than most people realise.
Colour marks are unusual in trademark law because colours are not invented – they already exist in the world, and in a sense they belong to everyone. If one brand can monopolise red, every designer loses access to a colour that fashion has used for centuries. The law is therefore cautious: the Trade Marks Act 1994 permits colour registration, but only where a brand can prove, through years of exclusive and consistent use, that consumers associate that colour with one commercial source and one alone. The bar is deliberately high, the evidence required is substantial, and the courts have never made it easy.
Louboutin cleared that bar in Europe. The Court of Justice of the European Union upheld its red sole trademark in 2018 in Louboutin v Van Haren Schoenen, confirming the mark was validly registered. That registration was automatically converted into a comparable UK trademark upon Brexit under the Intellectual Property (Eutrademark and Community Design) (Amendment etc) (EU Exit) Regulations 2019. But the European Union (Withdrawal) Act 2018 means UK courts are no longer bound by that EU ruling. A domestic challenger to the red sole today would face an untested legal landscape – one the UK Intellectual Property Office has done nothing to clarify.
This article examines whether UK trademark law adequately protects single-colour marks in the luxury fashion industry, using Louboutin’s red sole as its central analytical lens. Section 2 establishes the legal framework; Section 3 analyses the law including the post-Brexit dimension; Section 4 examines key cases; Section 5 offers critical findings; Section 6 concludes with recommendations.
2. BACKGROUND AND CONCEPTUAL FRAMEWORK
Trademark law starts with a deceptively simple idea: a sign that tells consumers who made something deserves legal protection. Section 1(1) of the Trade Marks Act 1994 defines a trademark as any sign capable of distinguishing the goods or services of one undertaking from those of others. The definition says nothing about what a sign must look like – a word qualifies, a logo qualifies, and in principle a colour qualifies too. But in practice, that principle is far harder to exercise than it sounds.
Words are invented by the brands that use them. Colours are different. Nobody created red. It has existed in fashion, art, design, and culture for centuries and belongs to everyone. When a brand registers a colour as a trademark, it is claiming exclusive rights over something that was already in the world, at a cost to every other designer who might want to use it.
Those conditions exist because of a genuine tension at the heart of this area of law. The red Louboutin sole, the Hermès orange box, the Tiffany blue represent deliberate brand-building, sustained investment carrying real commercial value. But colours are finite. If one brand can monopolise red soles, every other shoemaker loses access to a colour they never agreed to surrender.
The legal answer is the doctrine of acquired distinctiveness. A colour that lacks inherent distinctiveness – which is almost every colour, standing alone – can still earn trademark protection if a brand uses it exclusively and consistently for long enough that consumers come to read it as a source identifier rather than simply a design choice. Proving this requires consumer surveys, sales data, and years of exclusive use. It is achievable, but deliberately demanding.
Internationally, Article 15 of TRIPS Agreement and Article 6quinquies of the Paris Convention both permit member states to allow colour mark registration without prescribing domestic conditions – leaving the hardest questions to national courts.
Scholars remain divided. Dinwoodie and Janis caution against propertisation of the competitive environment through non-traditional marks. While luxury law scholars counter that for houses whose identity is inseparable from their visual signature, colour protection is trademark law at its purposeful application.
3. LEGAL ANALYSIS
3.1 The Distinctiveness Hurdle
The first obstacle facing any colour mark applicant under UK law is section 3(1)(b) of the Trade Marks Act 1994, which prohibits the registration of marks devoid of distinctive character. A single colour is almost always insurmountable at first application. It reads as decoration not as a brand signal. When Louboutin first applied its signature red on the outsole of its heel in 1993, that colour told most customers nothing about who made the shoe. It was simply red.
But that is precisely the point. The law does not require a colour to be inherently distinctive – it requires proof that distinctiveness has been acquired. Today, a consumer who glimpses a red lacquered sole across a room will, in all likelihood, think Louboutin before they think red. That recognition built over thirty years of exclusive use, global advertising, and cultural saturation is the legal evidence of acquired distinctiveness that the proviso to section 3(1)(b) was designed to reward.
The critical difficulty, however, lies not in whether Louboutin can meet this standard but in who else realistically can. Establishing acquired distinctiveness requires consumer recognition surveys, advertising records, and evidence of exclusive use spanning decades – an undertaking only the largest luxury houses can afford. For an independent designer with five or ten years of distinctive colour use, the same protection is theoretically available but practically out of reach. This asymmetry is a structural flaw, one that entrenches the advantages of established brands while offering little protection to the creative talent that drives fashion forward.
3.2 The Post-Brexit Dimension
The most underappreciated legal risk facing Louboutin’s UK trademark is the one Brexit created. Before Brexit, domestic courts were bound by CJEU authority. The 2018 ruling in Louboutin v Van Haren Schoenen – which confirmed that the red sole was not excluded from trademark protection as a sign giving substantial value to goods – therefore provided a secure legal foundation across both jurisdictions simultaneously. That security no longer exists.
Under section 6 of the European Union (Withdrawal) Act 2018, UK courts are not bound by post-exit CJEU authority. Louboutin’s EU trademark registration was automatically converted into a comparable UK trademark under the Intellectual Property (Eutrademark andCommunity Design) (Amendment etc) (EU Exit) Regulations 2019, and that converted mark carried its previous validity with it. But validity at conversion does not guarantee immunity from future domestic challenges. A claimant seeking to invalidate Louboutin’s UK mark today could ask a domestic court to assess the question entirely independently – without deference to the 2018 EU ruling – and no UK court has yet been asked to do so. The outcome is genuinely unknown.
The UK Intellectual Property Office Work Manual confirms that retained EU principles continue to guide examination practice, but administrative guidance is not binding judicial authority, and the Work Manual says nothing specific about the post-Brexit standard for colour mark acquired distinctiveness. This silence creates a legal vacuum that luxury brand owners are navigating without a map. The UK IPO should address this gap directly and urgently. The longer it persists, the greater the cost to every brand relying on a converted colour mark for UK protection.
3.3 The Functionality Gap
A further structural weakness in UK colour mark law is the absence of an express functionality doctrine. In the United States, the Supreme Court established in Qualitex Co v Jacobson Products Co that a product feature essential to its use or commercial value cannot be trademarked – a clean, principled rule distinguishing protectable brand identity from unprotectable product design. UK law has no direct equivalent. Section 3(1)(e) of the Trade Marks Act 1994, excludes shapes and characteristics that give substantial value to goods but colour has not been clearly brought within its scope. Applied to Louboutin specifically, this gap is acute – the red sole simultaneously functions as a source identifier and contributes to the shoe’s desirability and premium commercial value, and UK law currently provides no clear mechanism for adjudicating where one ends and the other begins.
A future UK challenger could argue that the red sole is not a source identifier at all – that it is a design feature that makes the shoe more desirable and commercially valuable, and that allowing one brand to monopolise it hands Louboutin a competitive advantage that trademark law was never designed to provide. Without an established framework, a domestic court would be working without guidance. The ambiguity is unnecessary and readily addressable through targeted legislative reform.
3.4 The Scope of Protection
Having a registered trademark and being able to enforce it are not the same thing. Infringement under UK and EU law requires proof of a likelihood of confusion among average consumers – and for a brand as recognisable as Louboutin, this creates a genuine paradox. A consumer paying upwards of several hundred pounds for a pair of heels is informed, brand-aware, and highly unlikely to mistake a competitor’s red sole for a Louboutin product. That sophistication, paradoxically, weakens the very infringement claim the brand most needs to bring.
The US Second Circuit’s resolution of this problem in Christian Louboutin v Yves Saint Laurent America is worth serious consideration. The Court held that the red sole infringes only when it contrasts with a differently coloured upper – the context in which Louboutin’s mark is commercially more significant – not where the entire shoe is red. This contrast principle limits the colour monopoly to Louboutin’s actual commercial use while preserving design freedom for competitors. In the absence of domestic authority, it offers a proportionate and principled model UK courts should adopt.
4. CASE LAW DISCUSSION
4.1 Christian Louboutin SAS v Van Haren Schoenen BV (CJEU, 2018)
In 2018, the Court of Justice of the European Union was asked to rule on whether Louboutin’s red sole trademark fell within the exclusion for signs that give substantial value to goods under Article 7(1)(e)(iii) of the EU Trade Mark Regulation. The case arose after Louboutin sued a Dutch retailer selling red-soled heels, and the Dutch court referred the question to Luxembourg. The CJEU held that colour per se is not a shape within the meaning of that exclusion — drawing a careful distinction between the colour red and the sole to which it applied – and confirmed that Louboutin’s mark was validly registered. This ruling is the legal foundation on which Louboutin’s red sole protection rests across Europe. Its significance for this article lies equally in what it no longer guarantees: under section 6 of the European Union (Withdrawal) Act 2018, UK courts are not bound by this ruling, and no domestic court has yet been asked to assess the red sole’s validity independently.
4.2 Christian Louboutin SA v Yves Saint Laurent America Holding Inc (2nd Cir, 2012)
When YSL released a monochromatic all-red sole – red upper and red sole – Louboutin sued for trademark infringement in the United States. The district court initially held red was functional in fashion and could not be monopolised. The Second Circuit reversed, upholding Louboutin’s mark as valid but limiting its scope through what has become known as the contrast principle: the red sole only infringes when it contrasts with a differently coloured upper. A fully red shoe, like YSL’s, does not infringe. This ruling is persuasive rather than binding in the UK, but its logic is directly relevant. It demonstrates that colour protection and design freedom are not mutually exclusive, offering UK courts a ready-made infringement framework that domestic case law has not yet supplied.
4.3 Société des Produits Nestlé S.A. v Cadbury UK Limited (2013 and 2022)
The Cadbury litigation offers the clearest available illustration of the UK’s approach to colour mark registration. In 2013, the Court of Appeal refused Cadbury’s application to register purple – Pantone 2685C – despite over a century of exclusive use. Describing it as ‘predominant’ was too imprecise to constitute a single registrable sign. A description that accommodates multiple visual forms cannot anchor a trademark. The 2022 High Court decision brought a different outcome. Cadbury reapplied with a reformulated description – limiting the mark to the Pantone number applied to the whole visible surface of the packaging – and the court allowed registration, finding the description sufficiently clear and backed by overwhelming evidence of acquired distinctiveness – built over more than a century – compelling. Together these cases establish that a colour mark is registrable, but the description must be technically exact and the evidence overwhelming. For Louboutin, commercial history is necessary but not sufficient – how the mark is defined matters as much as the evidence behind it.
4.4 Libertel Groep BV v Benelux-Merkenbureau (CJEU, 2003)
In Libertel, the CJEU confirmed that colours are in principle registrable as trademarks but that the distinctiveness requirement must be applied strictly, given the public interest in not restricting the colour availability. Libertel had applied to register orange for telecoms services, submitting only an orange swatch without further description or evidence. The application failed. The ruling established the foundational tension running through all colour mark law: the law will protect colour, but only where the case is overwhelming. As retained EU case law, Libertel anchors the principle that colour availability is a legitimate public interest concern UK courts must now weigh independently.
5. CRITICAL ANALYSIS AND FINDINGS
Three findings emerge from this analysis, together revealing a legal framework that is theoretically sound but practically inadequate for luxury brand protection in post-Brexit Britain.
The first concerns access. The acquired distinctiveness requirement sounds fair in theory – use your colour exclusively for long enough, and the law will protect it. But consumer surveys, global advertising records, and decades of exclusive use are not tools available to most designers. The difficulty with this approach is that it transforms a theoretically universal protection into one only the wealthiest brands can exercise. Louboutin can meet the standard. An independent designer with five years of distinctive colour use and limited resources cannot. A legal framework that incentivises creativity only for those who are already successful is not doing what intellectual property law was designed to do.
The second finding concerns Brexit. The conversion of Louboutin’s EU mark into a UK trademark carried no guarantee the legal reasoning securing it would survive domestic scrutiny. UK courts are free to approach the question independently and the UK IPO has provided no guidance on what standard they should apply. Luxury brands cannot build IP strategies around judicial likelihood. They need legal certainty, and the current framework does not provide it. The jurisdictional fragility of colour mark protection is not unique to the UK – in 2022, Japan’s Patent Office Appeal Board rejected Louboutin’s red sole trademark application on the basis that red soles had become ordinary commercial practice in the Japanese footwear industry, illustrating that even the world’s most recognised colour mark offers no guaranteed cross-border protection.
The third finding is the most straightforward to fix. The law fails to account for the tension between colour as a brand signal and colour as a product feature in any principled way. The US functionality doctrine resolves this tension cleanly, UK law has no equivalent for colour. A challenger who argues that the red sole adds commercial value to the shoe – rather than identifying its maker – would find UK courts navigating unfamiliar doctrinal territory. That gap is unnecessary. It is simply an unaddressed one – and the legislature should address it.
6. CONCLUSION
This article has examined whether UK trademark law adequately protects single-colour marks in the luxury fashion industry, using the Louboutin red sole as its central analytical lens. The analysis reveals a framework that is theoretically capable but practically inadequate. The acquired distinctiveness requirement favours established luxury houses over emerging designers, an outcome that ill-serves the broader objectives of intellectual property law. The post-Brexit conversion of Louboutin’s EU mark does not guarantee continued protection and the UK IPO’s silence leaves luxury brand owners navigating genuine uncertainty. The absence of a functionality doctrine compounds this further.
Three reforms are recommended. First, the UK IPO should issue specific guidance on the post-Brexit standard of acquired distinctiveness for colour marks. Second, Parliament should introduce an express functionality doctrine applicable to colour under the Trade Marks Act 1994. Third, UK courts should adopt the US Second Circuit’s contrast principle as a proportionate framework for infringement analysis.
The red sole has survived every challenge brought against it so far. Whether it survives the post-Brexit legal landscape will depend not on its commercial recognition – which is beyond doubt – but on whether UK law has the clarity and ambition to protect it.
BIBLIOGRAPHY
Legislation
Trade Marks Act 1994
European Union Trade Mark Regulation (EU) 2017/1001
Intellectual Property (Eutrademark and Community Design) (Amendment etc) (EU Exit) Regulations 2019, SI 2019/638
European Union (Withdrawal) Act 2018
International Instruments
Agreement on Trade-Related Aspects of Intellectual Property Rights 1994 (TRIPS)
Paris Convention for the Protection of Industrial Property 1883
Cases — UK and EU
Christian Louboutin SAS v Van Haren Schoenen BV (C-163/16) [2018] ECLI:EU:C:2018:423
Libertel Groep BV v Benelux-Merkenbureau (C-104/01) [2003] ECR I-3793
Société des Produits Nestlé SA v Cadbury UK Ltd [2013] EWCA Civ 1174
Société des Produits Nestlé SA v Cadbury UK Ltd [2022] EWHC 1671 (Ch)
Cases — United States
Christian Louboutin SA v Yves Saint Laurent America Holding Inc, 696 F3d 206 (2d Cir 2012)
Qualitex Co v Jacobson Products Co, 514 US 159 (1995)
Secondary Sources
G Dinwoodie and M Janis, Trademark Law and Theory (Edward Elgar 2008)
M Kindred, ‘Red Bottom Heels: The Trademark Dispute’ (2023) 91 University of Cincinnati Law Review
Official Publications
UK IPO, Work Manual: Chapter 2 — Absolute Grounds for Refusal (2023) < https://www.gov.uk/guidance/work-manual-chapter-2-absolute-grounds-for-refusal > accessed 6 June 2026
