"Exercise Unified Response," coordinated by the London Fire Brigade, simulated a tower block collapsing into Waterloo station to prepare specialist emergency crews for a largescale operation with mass casualties.
The four-day exercise which started today is designed to test the contingency planning of more than 70 organisations including local councils, utility companies and specialist search and rescue teams alongside disaster victim identification teams from Denmark, Germany, the Netherlands, Belgium, Luxembourg, France, Italy and Spain.
"It's not often we get to test working practices on such a scale and it's really positive to see so many of our European colleagues involved."
A total of 2,000 volunteers and actors will act as the casualties over four days and four separate venues in London as well as a disused power station are being used for the exercise.
A mock-up Tube station has been created and seven carriages upturned in the rubble.