A multi-agency terrorism training exercise staged at Watford Football Club on Saturday has been hailed a success.

The simulation started with a traffic incident outside the stadium before becoming a mass casualty exercise within the grounds.

The scenario was based on a marauding terrorist threat within the ground, and the tactical response of police and partners.

Dozens of volunteers braved chilly conditions to act as “casualties”, and give exercise “Heron” an authentic feel for all those taking part.

Chief Superintendent Richard Liversidge was the force lead on the exercise.

“This timely and highly relevant exercise was designed to test our multi-agency response to an ongoing incident involving mass casualties,” he said.

“This is a complex task, and such responses require the commitment of all agencies and many other responders and organisations.

“This exercise replicated some of that complexity, and could not have been undertaken without the hard work of the planners, role players, and enthusiasm and willingness of wider organisations to work together.”

The training session involved the East of England Ambulance Service, Hertfordshire Constabulary, Hertfordshire Fire and Rescue Service, the local NHS Trust and Watford General Hospital, Regional Military Liaison, and a range of stakeholders including Watford Football Club and the Premier League.

While a level of disruption was anticipated ahead of the exercise, no concerns related to the event were raised with police.

Chief Superintendent Liversidge added: “Thank you to all those who took part on Saturday and to Watford Football Club for providing an excellent venue for the exercise scenario.”

Glyn Evans, Watford FC’s operations director, said: “It was our privilege to host an exercise that demonstrated good communication and highly collaborative working to be at the forefront of everyone’s thinking.

“Our special thanks to the volunteers who came along to ensure a very meaningful day.”

Participants will get to share their experiences of the exercise during a dedicated de-brief.