What is the 'Deconfliction Service'?
A deconfliction service is a specific type of air traffic service.

Normally, outside of controlled airspace, air traffic controllers do not alert pilots of potential encounters with other aircraft (conflicts).

However, there my be other services offered outside of controlled airspace, typically these are Flight Information Services (FIS).

In the UK, four air traffic services are distinguished outside controlled airspace: Basic Service, Traffic Service, Deconfliction Service and Procedural Service


  A Basic Service is an ATS provided for the purpose of giving advice
  and information useful for the safe and efficient conduct of flights.
  This may include weather information, changes of serviceability of
  facilities, conditions at aerodromes, general airspace activity
  information, and any other information likely to affect safety. The
  avoidance of other traffic is solely the pilot’s responsibility.


source: UK Flight Information Services CAP 774, February 2015

Note the last sentence.

The deconfliction service is defined as:


  A Deconfliction Service is a surveillance based ATS where, in
  addition to the provisions of a Basic Service, the controller provides
  specific surveillance-derived traffic information and issues headings
  and/or levels aimed at achieving planned deconfliction minima, or for
  positioning and/ or sequencing. However, the avoidance of other
  traffic is ultimately the pilot’s responsibility


Again, note the last sentence.