The live exercise carried out by nearly 20 different agencies across Sussex, including Mid Sussex, drew to a close at 7pm yesterday (Wednesday May 14) evening.
The major incident exercise involved nearly 400 people from the emergency services, local authorities, health trusts and other agencies and included 200 volunteers as victims and witnesses.
Steve Voice, exercise director, said: “The scenarios we tested were exceptional and of a scale that tested our resources and provided very realistic settings at Brighton, Eastbourne and Slaugham Manor.
“We will be looking at the results of the exercise to see if there are areas of improvement that can be made to ensure that, should an event like this really happen, all emergency services work together effectively.
“We endeavoured to keep disruption to the public to a minimum and appreciated their support and understanding at those locations. I want to thank all those who took part, especially the volunteers who helped make it so realistic.”