This is an issue that people have been divided on for some 20 years. I don't think we need to change the number of departments. What's really important is to establish the essence of each department in advance. We would need a central department. During the Second World War, there was the Department of Defence Production that centralized everything related to military procurement.
Today, the same priorities would exist. There would be regional priorities, innovation, technology. They would simply be concentrated in one department. The same pressures, the same conflicts, would exist.
I don't think there is an ideal solution. A number of our allies have created an agency, rather than a department. Sometimes it's more efficient, and sometimes it's not. The advantage of an agency is that it's a little bit further removed from ministerial interference or intrusion. Sometimes it's useful for ministers not to interfere in the details, but not always.
So an agency can be created rather than a department. That's one way.