In the UK, it was formerly a hybrid between class E (controlled) and G (uncontrolled) as Advisory Routes (ADRs).
[8] ATC does not exercise any executive authority in uncontrolled airspace, but may provide basic information services to aircraft in radio contact.
[5] The aircraft commencing its flight in uncontrolled airspace, and subsequently proceeding into controlled airspace, should obtain clearance from the ATC unit in whose area the controlled part will begin.
Aircraft operating under IFR should not expect separation from other traffic; however, in certain uncontrolled airspace, this might be provided on an 'as far as is practical' advisory basis.
Controlled flights should not be vectored (directed) by ATC into uncontrolled airspace except for weather avoidance or in an emergency.