A private plane's cabin door opened mid-flight, forcing the pilot to return to London Biggin Hill Airport.

The incident occurred on June 1 and involved a Beechcraft King Air C90GTx, registered as D-IMEP.

No passengers were on board at the time, and the lone pilot was uninjured.

The aircraft had taken off and was climbing to 1,700 feet when the pilot noticed the cabin door warning light flickering before it became steadily illuminated.

Simultaneously, a bang was heard, and the pilot realised the cabin door had opened.

The pilot declared a "PAN" emergency call, a precautionary measure, to air traffic control and returned to the airport for a safe landing.

CCTV footage from the airport apron confirmed the external door handle was in the closed position before takeoff.

The pilot had completed both visual and mechanical checks to ensure the door was locked before departure, as detailed in the aircraft's checklist and Pilot Operating Handbook.

The manufacturer of the aircraft noted that only two other similar incidents have been recorded on the King Air 90 series.

The incident serves as a reminder of the importance of pre-flight door security checks.