This thread is about UK airspace,
Yes....and we know how perfectly coordinated that can be...right?
At least the Fee Structure for using it anyhow!
I watched a MidAir occur at what is now an International Airport between a DC-9 Airliner which overflew a C-172 when both were on a straight in final to an Instrument Runway...in very nice weather...with both Approach Control and Control Tower in operation.
There are always going to be conflicts, failure to see other traffic, and tragedies no matter the technology and complexity of air traffic de-confliction efforts using technology and other methods.
Sadly, I was in the process of cranking an aircraft and just happened to glance up to see the two aircraft in less than a couple of seconds of colliding and could not do a thing but look on as the Cessna came apart....lost one wing...and strike the ground a few meters from the Wind Sock.
The DC-9 suffered minor damage to the fuselage and landing gear struts and landed safely.
These sad events bring home the notion the Sky can be a very small place at times.