This chapter explores a broad context setting of Brexit drawing on literature and relevant policy documentary source materials. It discuses the findings through the lens of transnational theory, which has not previously been adopted to examine this specific policy field. Discussion of the findings at both transnational and local scales are analysed separately to identify the transnational challenges and local consequences, and then a synthetic section links the transnational to the local scale to show that relationships and inter-connections across spatial levels within policing, security and criminal justice may have detrimental impacts on how agencies respond to an escalation in vulnerable individuals and groups at local levels. Global shifts are impacting greatly on local economies with rises in terrorism, international crime, people trafficking, drug smuggling and many other issues facing Police Leaders who are already dealing with a multitude of domestic policy issues.