The research is based on the hypothesis that there are various situations in the application of the tariff classification rules, in which uniformity is given unjustifiably greater importance than legal certainty. This led to the following research questions:

• To what extent does the aim for uniformity in tariff classification in the EU lead to disproportionate infringements of legal certainty?
• What improvements to tariff classification measures and procedures can be considered that mitigate the disproportionate infringements, if any, of the legal certainty?
• What improvements can be considered to effectively remedy these infringements in court if not mitigated?

This research has shown several instances where, in my view, there is a breach of legal certainty in favour of the principle of uniformity. Some of these breaches can in my view be considered disproportionate. One example is the fact that a BTI can be revoked due to not officially published guidance of the Nomenclature Committee. Another example is the potential extended term for post-clearance recovery of import duties in case of a change in interpretation of the CN. In addition, this research has mainly shown the complexity of tariff classification due to the abundance of sources for tariff classification purposes, the sometimes confusing application of these sources by the various stakeholders and a lack of accessibility of these sources. Moreover, through this uncertainty there is, in my view, a lack of uniformity because the rules that need to be followed are unclear, unreliable and untransparent which can result in different interpretations by various stakeholders of the same rules, potentially leading to misunderstandings and disputes. Instead of only looking to increase uniformity, in my view it should be turned around and the increase in legal certainty should be looked at. As legal certainty increases, in my view, the uniformity will increase. In that sense, uniformity and legal certainty are indeed two sides of the same coin.