The Virgin Atlantic Airways flight VS687, heading for JFK airport in New York, triggered an emergency Squawk 7700 while flying near Swindon, according to several flight watchers on Twitter.

       The Airbus A330-343 took off from Heathrow in London just before 5pm.

       The aircraft, which was built 10 years ago, was flying at around 15,000ft when the alert was sent, the flight watchers claimed.

       But the airline denied this was the case, with Virgin Atlantic telling Express.co.uk that a cargo-only flight en route to JFK never issued an emergency at any time.