As strong as the weakest link. Transport and supply chain security

The supply chains form a complicated interlinked system where any disruption, at any possible level, can affect the network itself but also its surrounding, including the society. This feature is confirmed by a well-known and often repeated statement that the chain is only as strong as its weakest link. This manuscript provides a comprehensive research-based rationale for this statement to shed new light on how the phenomenon could be identified and what are theoretical grounds for its management. The scoping review allowed for exploring the existing literature on the weakest links in supply chains to clarify this complex concept and explain its heterogeneous nature. To structure our research, we have adopted two theoretical perspectives, present in existing studies, that is network interdependency and weakest link public good. The study contributes to the existing body of knowledge by summarising literature in the field, identifying gaps, and setting the agenda for future research. It concentrates on two areas derived from literature, that is the ways of identification of weakest links and the determination and provision of the optimal level of security. The analysis reveals that there is no consensus even regarding the weakest link definition. The majority of studies are theoretical and general with little research devoted to the practical implications. While equilibriums for optimal resource allocation are well recognised specific measures oriented at the elimination of the weakest link are lacking. As a result, we identify gaps in the existing body of knowledge regarding threat-weakest link occurrence, countermeasures, and policy options offered.