Emergency services in Brighton were put to the test today. An explosion was staged at a disused army barracks to see how police, fire and ambulance crews would respond.
Around 200 volunteers took part with other incidents staged across Sussex.
Andy Dickenson reports and speaks to Insp Tony Lumb from Sussex Police and Mark Rist from East Sussex fire and Rescue.
More top news
Tuesday's weather for the west of the region
Tuesday's weather for the east of the region
The government is consulting on proposals to introduce an hourly fast train in parts of the south east - not stopping at some stations