Metropolitan Police sealed off Kensington Gardens in London on April 17, 2025, after the pro-Iranian Islamist group Harakat Ashab al-Yamin al-Islamia posted a video claiming to have launched drones containing radioactive material toward the Israeli embassy. The video showed two individuals dressed in hazmat suits launching drones. A chemical, biological, radiological, and nuclear (CBRN) unit was deployed to the park, which remained closed for two days.

Neither the incident in Kensington Gardens nor a related event in Medyka resulted in casualties. Previous incidents involving hazardous substances in the UK include the assassination of Alexander Litvinenko in London, the Novichok attack on Sergei and Yulia Skripal in Salisbury, and the poisoning of Alexei Navalny on a flight over Siberia. In October 2024, authorities discovered a plot to place incendiary devices on cargo planes destined for North America.

European Union and NATO policy documents identify protection from CBRN threats as a national responsibility essential for societal resilience. Historical events such as the Chornobyl nuclear meltdown led to the creation of systems like the European Community Urgent Radiological Information Exchange and the European Radiological Data Exchange Platform, designed to track large-scale atmospheric contamination. The EU's Preparedness Union Strategy, ProtectEU Internal Security Strategy, and CBRN Action Plan acknowledge limitations in the bloc's CBRN detection and response capabilities.

The rescEU strategic reserve, valued at over €500 million, provides medical countermeasures and protective equipment for CBRN incidents. This reserve is coordinated by the Directorate-General for European Civil Protection and Humanitarian Aid Operations (DG ECHO) and the Directorate-General for Health Emergency Preparedness and Response (DG HERA). Negotiations for the EU's next long-term budget, the Multiannual Financial Framework for 2028-2034, are currently in the scoping phase.