Transatlantic intelligence sharing between the UK, U.S., and EU remains vital against Islamist and far-right terrorism. Cooperation gains significance amid rising extremist violence and evolving tactics. Post-Brexit, strengthening intelligence ties is essential for security, balancing diplomacy, legal complexities, and privacy concerns while ensuring effective collaboration across national systems and laws.
Intelligence Sharing and Security Cooperation
The transatlantic partnership has developed sophisticated mechanisms for intelligence exchange. The EU-U.S. Terrorist Finance Tracking Programme (TFTP) alone has produced more than 16,700 intelligence leads since 2010, highlighting the scale of collaborative efforts to disrupt terrorist financing channels. Following the 2013 Snowden disclosures, trust was initially damaged but restored through binding data protection agreements in 2015 and 2016 that formalized privacy commitments. The Passenger Name Record (PNR) agreement has been vital for sharing airline passenger data between the EU and U.S. since 2004; after Brexit, the UK-EU Trade and Cooperation Agreement maintained this essential framework for the UK. Additionally, the Secure Information Exchange Network Application (SIENA) platform is a key tool for real-time intelligence sharing among EU member states, Europol, and U.S. agencies such as the FBI. In 2025, this platform expanded its scope to cover far-right threats. Domestically, the UK passed Martyn’s Law (Terrorism Protection of Premises Act 2025), mandating enhanced protective measures in public venues.
Islamist Terrorism
Islamist extremist groups like ISIL and Al-Qaeda remain the primary targets of transatlantic intelligence collaboration. The UK has successfully foiled at least 12 Islamist terrorist plots since 2017, underscoring the persistent and evolving threat. Cooperation includes intelligence sharing on finance, movements, and online radicalization efforts.
Far-Right Terrorism
An urgent shift has emerged in intelligence sharing efforts to counter far-right terrorism. The UK has proscribed five far-right extremist groups since 2016, including the white supremacist National Action. The EU officially designated the far-right group The Base as a terrorist organization in 2024, reflecting heightened awareness of the threat. UK intelligence agencies have adapted by deploying behavioral science units to detect and prevent radicalization, focusing on this non-Islamist form of extremism as a political priority.
Historical and Political Context
Transatlantic intelligence cooperation has deep roots dating back to World War II, initially characterized by bilateral U.S.-UK ties. The September 11 attacks catalyzed institutionalized multinational cooperation, notably between the U.S., UK, and the EU through Europol. However, the 2013 NSA surveillance revelations temporarily strained these ties. Significant progress followed with the introduction of legal frameworks protecting data privacy in intelligence exchanges. Brexit introduced a new set of challenges, complicating access to EU databases and intelligence platforms. Despite this, the UK-EU Trade and Cooperation Agreement has ensured continued, though nuanced, collaboration. The evolving threat landscape now requires intelligence cooperation to address far-right terrorism on an equal footing with Islamist terrorism.
Main Actors and Strategic Stakeholders
The main actors in this cooperation include national intelligence and law enforcement agencies such as MI5 in the UK and the FBI and NSA in the U.S., complemented by EU institutions like Europol and the European External Action Service (EEAS). The UK government prioritizes maintaining operational autonomy while fostering close transatlantic ties. On the political spectrum, the Conservative Party emphasizes stringent national security measures and expanded counterterrorism powers, evidenced by support for Martyn’s Law. Meanwhile, opposition parties, including Labour and the Liberal Democrats, advocate for a stronger emphasis on civil liberties and data protection safeguards. Civil society groups remain vigilant about potential overreach and the impact of counterterrorism laws on Muslim communities and legitimate protest activities.
Recent Policy and Security Developments
The Second EU-UK Counter-Terrorism Dialogue held in February 2025 reinforced commitments to joint threat assessments, better coordination of intelligence sharing, and enhanced technology use to combat terrorist content online. The UK’s adoption of Martyn’s Law in April 2025 marked a significant legislative step to mitigate physical terrorism risks by imposing stricter security obligations on publicly accessible places. The recent UK Integrated Review and National Security Strategy demonstrate adaptive resource allocation between Islamist and far-right threats. Moreover, political momentum in the EU to add far-right groups onto terrorist entity lists signals a broader recognition of the multifaceted nature of terrorism today. However, debates persist around data privacy, legal authority, and sovereignty issues that could shape future frameworks.
Key Challenges and Political Risks
One of the foremost challenges is navigating the tension between robust security and privacy rights. Differences in national data protection laws between the UK, EU, and U.S. complicate intelligence sharing consistency. Brexit remains a complication, risking delays and inefficiencies in cross-channel intelligence flows, critical for timely threat disruption. The rise of far-right terrorism presents a strategic challenge, requiring law enforcement to pivot from traditional Islamist-focused approaches. Furthermore, counterterrorism legislation risks marginalizing minority communities and provoking political backlash if perceived as unjust or overbroad. The rapid advancement of communication technologies demands continuous modernization of surveillance capabilities without undermining the democratic rule of law.
Political and Policy Implications
The ability to maintain strong transatlantic intelligence ties strengthens domestic security and reassures voters concerned about terrorism. For the UK, harmonizing security cooperation with the EU post-Brexit showcases pragmatic diplomacy amid broader political divisions. The ongoing fight against both Islamist and far-right extremism affects international alliances, emphasizing mutual dependencies in global security architecture. Internal political debates reflect a balancing act between enforcing security measures and protecting civil liberties, which influences policymaking and public opinion. Recognition of far-right terrorism as a significant threat aligns with emerging political realities and voter concerns about domestic extremism. The evolution of data sharing agreements and legal frameworks will also impact wider transatlantic negotiations, including trade and diplomatic relations.
