The ICAO Annexes and PANS specify the minimum level of service to be provided to IFR and VFR flights in different classes of airspace. They do not preclude the application of separation in other circumstances.
bookworm, I've got it now - you must work for the CAA. That's the sort of cop-out they love to use whenever they're backed into a tricky corner.....or, perhaps, preparing for an ICAO audit!