Flight BA336 from London Heathrow to Marseille was forced to return.
The flight departed London Heathrow at 07:20 BST to Marseille where it was expected to land at 09:50 CEST.
About 30 minutes after take off, while cruising at 33,000 ft, the crew declared an emergency.
The pilots contacted ATC about a technical problem which could be a pressurization issue.
The Airbus A320 (reg. G-EUUC) performed a rapid descent to 10,000 ft.
The 21 year-old aircraft landed back at London Heathrow almost 1h30 after departure.
British Airways sent this statement to AIRLIVE: “The flight returned to London Heathrow as a precaution due to a minor technical issue. It landed safely and customers disembarked as normal. We’ve apologised to our customers for the disruption to their journey and our teams are working hard to get them on their way as soon as possible.”