title_body: Recommend safe distance from other drone flyers When going to fly my drone, I notice there are a few other drone flyers as well.
  
  What is the recommended safe distance to be kept from other drone users in order to not cause an accident?
upvoted_answer: In this situation, I would approach the other flyer(s) to say hello and discuss this with them to prevent misunderstandings or differences of opinion - for example, if the other flyer is new they might want much larger separation than you think is enough, whereas if you are both experienced you might be happy flying in close quarters.
  
  Also, it might make life easier if you stand close to each other; I've done this before (albeit with people I knew) and it is useful to regularly share information like "I'm at 200 ft by the tree on the left", "Thanks, I'm at 50 ft moving across to the right" - and of course warnings like "Unleashed dog approaching!" and "Helicopter!"
  
  
  
  If you are looking for official guidance, you could check CAP 393 Article 95:
  
  
    95.—(1) The SUA operator must not cause or permit a small unmanned surveillance aircraft to be  flown  in  any  of  the  circumstances  described  in  paragraph  (2),  and  the  remote  pilot  of  a  small  unmanned surveillance aircraft must not fly it in any of those circumstances, except in accordance with a permission issued by the CAA.
    (2) The circumstances referred to in paragraph (1) are—
     (a) over or within 150 metres of any congested area;
     (b) over or within 150 metres of an organised open-air assembly of more than 1,000 persons;
     (c) within 50 metres of any vessel, vehicle or structure which is not under the control of the SUA operator or the remote pilot of the aircraft; or
     (d) subject to paragraphs (3) and (4), within 50 metres of any person.
    (3) Subject to paragraph (4), during take-off or landing, a small unmanned surveillance aircraft must not be flown within 30 metres of any person.
    (4) Paragraphs  (2)(d)  and  (3)  do not  apply  to  the  remote  pilot  of  the  small  unmanned surveillance aircraft or a  person under the control of the remote pilot of the aircraft.
    (5) In  this  article,  “a small  unmanned surveillance aircraft”  means  a  small  unmanned aircraft which is  equipped to undertake any form of surveillance or data acquisition. (b)
  
  
  I am not aware of any specific rule for separation in relation to other drones, unless they were to be considered a vehicle for rule 95(2)(c) in the quote but elsewhere in CAP393 they use "flying machine" to refer to (any) aircraft.
  
  However, as always, there is the 'catch-all' in Articles 94 and 241 should something go wrong:
  
  
    94.—(1) A person must not cause or permit any article or animal (whether or not attached to a parachute) to be dropped from a  small unmanned aircraft so as to endanger persons or property.
    (2) The  remote pilot of  a  small  unmanned aircraft  may  only  fly  the  aircraft  if  reasonably satisfied that the flight can safely be made.
    (3) The  remote  pilot of  a  small  unmanned aircraft  must  maintain  direct,  unaided visual contact with the aircraft sufficient to monitor its flight path in relation to other aircraft, persons, vehicles, vessels and structures for the purpose of avoiding collisions.
  
  
  and
  
  
    
    A person must not recklessly or negligently cause or permit an aircraft to endanger any person or property.