An RAF training plane came dangerously close to colliding with a model aeroplane flown by an enthusiast near Market Deeping, according to a report.
The report states the plane flew within just 40 feet of the remote-controlled model aircraft, which was flying at 600 feet.
A UK Airprox Board report labelled the incident on February 4 last year as “high severity” and said the “safety of the aircraft may have been compromised”.
The trainer, from RAF Wyton near Huntingdon, had to take evasive action when the near-miss happened above the village of Northborough.
The model’s operator thought his plane - a white, low-wing Seagull RC - was flying at up to 150 feet but the RAF trainer confirmed it had been flying above it at one point at 600 feet.
The report stated that a local model aircraft flying club had been permitted to use the airspace.
The Airprox Board report concluded “safety margins had been much reduced”.
The board suggested because nearby RAF Wittering had changed to a non-flying base users of the airspace had become less aware of dangers.
It said all operators in the area needed to be alert to each other’s activities.
The Ministry of Defence pointed out that RAF Wittering has since returned to flying status.