June 22, 2016

TSG IntelBrief: The Security Implications of Brexit

• The referendum in the UK on continued membership of the EU will take place on June 23; security issues have featured prominently in the debate

• Both sides have claimed security advantages in support of their argument to leave or remain; in reality, the terrorist threat will remain ‘severe’ in the UK whatever the result of the vote

• The Islamic State and other terrorist groups aim to promote tension between Western states and erode European unity

• Terrorist organizations are right to think that close security cooperation within Europe is a major brake on their activities.


Whether intentionally or not, the murder of British MP Jo Cox on June 16, apparently by a right-wing nationalist concerned at her empathy with refugees, has underlined the major role played by security issues in the debate over the rights and wrongs of the UK’s membership of the EU. Those who support ‘leave’ claim that immigration is too little controlled under EU rules and so undermines security. They also argue that the European Court can prevent the UK from deporting people who are considered a security threat. Those who support ‘remain’ point to the fact that immigration controls are in fact stronger when the EU members share information and cooperate, and that the role of the European Court is to uphold the law, not to make it.

The arguments about security are by now largely peripheral to a debate that has become more emotional than rational, and so far as the terrorist threat is concerned, the UK can safely rely on its partners in Europe to alert it to any suspicion of an attack, regardless of Britain’s membership of the EU. The UK likewise will continue to pass relevant information to its European partners whatever the result of the referendum, just as it does to its non-EU allies. In post-incident investigations, close cooperation on terrorism will remain the norm in Europe, regardless of border arrangements or political agreements on union.

But effective operational cooperation depends on more than an efficient system for passing messages. It relies on close personal relationships between members of security services or law enforcement agencies and their foreign counterparts. It is extremely rare that a terrorist plot with an overseas dimension is disrupted because a partner service is able to provide full detail of people, method, time, and place. Far more often the value lies in the provision of a piece of information that is only significant when matched with other pieces. This sort of exchange is highly dependent on a regular discussion between professionals of the threat, including shared analysis of the operational objectives and methodological developments of the enemy. Through informal discussion and exchange of views and ideas, experts are far better able to sift through the myriad leads that cross their desks every day and to prioritize investigations.

Britain’s security, with the possible exception of Northern Ireland, where issues are more local, is inextricably linked with the security of its European partners. The so-called Islamic State and al-Qaeda, which present the most imminent terrorist threats, make no distinction between an attack in Paris or one in London, just as they make no distinction between an attack in London and one in New York. Their decisions on locality are determined solely by opportunity. As of now, it appears that the Islamic State has a greater pool of terrorist operatives associated with France and Belgium—so giving those services a more important role in counterterrorism—than with the UK or Germany. But a successful attack in London or Berlin would certainly achieve the impact of further attacks in Paris or Brussels, and must be an equally important terrorist objective. 

Reports that Abdelhamid Abaaoud, the ringleader of the Islamic State attack in Paris last November, had photographs of British landmarks on his telephone, raise questions about his plans as well as about his ability to enter the country although wanted by the Belgian police. Whatever the story, it is unlikely to have had anything to do with UK membership of the EU, as all passports are checked at UK ports of entry regardless of citizenship. Nonetheless, the likelihood of someone slipping into the country whose terrorist affiliations are known or suspected is greatly increased when the political climate discourages or denies the opportunity for frequent operational exchange, whether formal or informal.

Furthermore, it is not just in the operational exchange that the UK benefits from its membership of the EU; it is also in the broader discussion of internal and external security policy. The voice of the UK carries weight in these important debates and its influence is welcomed both by EU countries and by outside partners such as the United States. In addition, the EU spends considerable amounts of money each year on improving the counterterrorist capacity of countries outside the Union, and its selection of place and project is informed in large part by the advice of security professionals. While a member of the EU, the UK can ensure that money is spent as efficiently as possible on improving the security and capacity of those states that are likely to have the greatest impact on the security of the UK.

The UK Security Service assesses the risk of a terrorist attack in the country as ‘severe’—its second highest level. Its assessment will certainly not change as a result of the referendum. But ensuring maximum opportunity for the informal exchange of information and analysis, and providing direct input into EU counterterrorism policies and assistance towards third countries, are key parts of Britain’s defenses. While protected by its island geography, the UK’s security is undoubtedly stronger as a fully engaged part of Europe. This is also the assessment of the Islamic State. In crowing over the impact of the Paris attacks, it mentioned specifically the weakening of European cohesion. 


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