Two parachutists narrowly avoided disaster when two F-15 jets flying at 350mph passed under them as they were in freefall, a report has revealed.
One captured the incident on a helmet-mounted camera, according to an air proximity report issued on Thursday.
The incident took place over Chatteris drop zone in Cambridgeshire in April.
The US fighters, based at RAF Lakenheath, Suffolk, were unaware of any parachuting activity in the area at the time, despite such information being made available every day.
The report graded the incident as the second highest category in terms of risk, stating that "safety had been reduced to below norm".
It has been said that it has been "ineffective".