A multi-agency simulation designed to test the effectiveness of a joint response to a marauding terrorist attack (MTA) near the Sellafield site has been widely praised.

The large-scale scenario – Exercise Merlin – took place at Griffin Park and focused on delivering a co-ordinated Operation Plato response involving Authorised Firearms Officers (AFOs) from the Civil Nuclear Constabulary (CNC) and Cumbria Constabulary.

For the first time, Sellafield AFOs deployed alongside their Cumbria counterparts, marking a key milestone in interoperability and regional preparedness.

Exercise Merlin aimed to validate the effectiveness of a joint tactical firearms response to an MTA scenario, test command handover procedures between the CNC’s Sellafield Incident Manager (SIM) and Cumbria’s Force Incident Manager (FIM), as well as strengthen tactical co-ordination among site-based and regional response units.

Assistant Chief Constable Mick Vance, who attended the exercise, praised the collaboration and professionalism on display. He said: “I want to extend my sincere thanks to all those who planned, supported and participated in this important multi-agency exercise. I understand the level of planning that goes into these events, and it was pleasing to see the co-ordination of partner agencies in response to a credible and challenging scenario.”

Feedback from participants was overwhelmingly positive, with all agencies highlighting the value of operating in a live, high-stakes simulation. Teams reported strong communication, clear leadership, and operational learning that will directly influence future planning and training.