Would Britain's response to a major disaster be weaker if we left the EU?
The rubble is real - there are thousands of tonnes of it.
No wonder. The planners of today's emergency services exercise have imagined a catastrophe of enormous scale - the collapse of a tower block onto the Underground station in Waterloo.
A disused power station in Kent fitted with unused train carriages plays the part of the packed Tube station; a thousand volunteers are performing as ‘casualties’. But hundreds of firemen and police officers are being asked to respond as they would if this were happening for real. Techniques required to deal with the aftermath of natural disasters, terrorist attacks and other man-made catastrophes are being tested.
Disaster drills like this are fairly common, but this is the biggest such exercise ever staged. Mortuaries, police services and even the Government’s Cobra emergency committee will be involved - too many agencies to name. But there are some participants here that shouldn't be ignored.
Specialists teams from Hungary, Italy and Cyprus have arrived to take part in the four-day exercise, named ‘Exercise Unified Response’. After all, the drill has been partially funded by the European Union, and was commissioned not only to test the ability of British agencies to respond to the disaster, but their European counterparts to assist.
Against the apocalyptic backdrop of ‘the Waterloo Tube disaster’, we are being shown European co-operation in action.
This scenario assumes that Britain’s urban search and rescue teams have been stretched by emergencies elsewhere - unconnected disasters in Staffordshire and Gloucestershire. And so, as UK authorities might be forced to do if this were 'real life', they have requested that Europe’s ‘Civil Protection Mechanism’ is activated.
The programme, established in 2001, is a method of fostering co-operation among emergency services and disaster agencies across the EU. It has been used to respond to emergencies within member states. For example,Greece asked for it to be triggered to cope with the migration crisis last December.
So does this show that the response to a disaster like this would be weaker if Britain left the EU?
The UK might still receive help - after all, the European mechanism was used to respond to the earthquake in Haiti and the Ebola out break in west Africa. Britain might even be able to contribute from outside the EU - as the governments of Turkey and Iceland do now.
If it left the EU, Britain would almost certainly seek ad hoc membership of co-operatives like this one. It's important to remember that as campaigners on both sides of the debate make selective claims about our security to boost their case.
Remember the argument that EU membership leaves us vulnerable to weapons and terrorists from Europe? That seemed to underestimate the impact of the English Channel, and the small fact that, if anything, we’re a net exporter of terrorism.
And what of the claim that departure from the EU might contribute to the dismantling of our international intelligence sharing relationships?That ignored the fact that the most important of these agreements are with the United States and other English-speaking nations.
This week's disaster drill rehearses an emergency that will hopefully never happen. But whether Britain is inside or outside the EU, it's response to it might not look hugely different.