DOZENS of police officers, firefighters and ambulance personnel descended on Pride Park this lunchtime.
Startled onlookers thought a real emergency was taking place but it was all part of Exercise Grosvenor.
A Derbyshire police spokeswoman explained that the exercise was an opportunity for all the emergency services to come together to test how they would respond in a large-scale emergency.
Advance publicity about the hush-hush exercise was kept to a minimum as the emergency services made their way down from junction 29 to 25 on the M1 and then headed down the A52 into Derby and Pride Park.
The exercise has now been completed but had focused on an area close to the iPro Stadium and near to where the city's velodrome is being constructed.
Derbyshire assistant chief constable Gary Knighton said: "The exercise is valuable in seeing the team approach as everyone comes together so that we can assess and respond to major incidents."
Startled Derby Telegraph photographer Lucy Shaw, who happened to be working on another job in the area, said she was surprsied to see so many emergency vehicles arrive at the same time.
She said: "I wondered what was going on and just headed towards where everyone was thinking it was a real emergency at first."
