REF: https://www.gov.uk/government/uploa...ft-systems-drones-mid-air-collision-study.pdf

Full story at BBC News: UK government's drone collision report criticised - BBC News
"The Drone Manufacturers Alliance Europe (DMAE) has questioned the evidence gathered in the report and says some of the testing is flawed.
The DfT said it could not comment for security reasons."

Full story at BBC News: UK government's drone collision report criticised - BBC News