- 1,000 emergency responders take part in two-day exercise
- Exercise comes just a week before 10th anniversary of London transport bombings
- Practice session is not in response to any specific intelligence, official says
London (CNN)How well can a major world city contain a deadly terrorist attack?
That's a question that more than 1,000 emergency personnel in London set out to answer on Tuesday and Wednesday.
It was a major anti-terrorism exercise -- one that had been months in the planning but that took on new significance after an attack on a Tunisian beach last Friday left many people dead, most of them Britons.
The exercise took place at a disused Underground station in central London. All the first police officers on the scene knew was that a lone gunman had disappeared into a subway station.
Outside, bodies lay sprawled on the pavement. Some were people supposedly injured; others were supposedly dead.
The object, obviously, was to help the injured as as effectively as possible -- and to find the gunman and halt his murderous spree.
Reaction of decision-makers tested
"Our first responders will be put through their paces by mounting an operation to contain the area, evacuate the public, rescue and treat the wounded, manage a crime scene and, importantly, catch the people responsible," said Maxine de Brunner, deputy assistant commissioner of the Metropolitan Police.
The exercise would also test the reactions of decision-makers and the ability of different agencies to communicate with each other, de Brunner said.
Called Operation Strong Tower, the exercise has been in the works since January. That it came days after the terrorist attack in Tunisia was a coincidence. It also came just a week before the 10th anniversary of the July 7, 2005, London transport bombings -- the deadliest terrorist attack ever in Britain.
De Brunner said the exercise was just part of keeping Britain's response effective, and she stressed that it was not being carried out in response to any specific intelligence.