Royal Air Force fighters were scrambled to intercept a civilian airliner that had reported a bomb on board.
The Air India jet was circling over Norfolk before the Typhoon interceptors met it.
An RAF spokesman said the alert ended without incident and the Boeing 777-300 “was released to continue to its original destination”.
The plane landed safely at Heathrow Airport some time later.
Audio of the passenger jet’s crew alerting air traffic control to the potential threat was recorded by a Dutch plane spotter.
In it, the captain can be heard telling ground controllers: “We have a suspected bomb on board, requesting priority landing.”
It continued: “We have a bomb threat. Air India 129 is requesting descent.”
The aircraft enthusiast, who would only be identified by his X user name, @EHEH_spotter, confirmed to the BBC that he had made the recording using a scanner.
A loud sonic boom was reported across Norfolk as the fighter jets raced to intercept the airliner.
BBC Radio Norfolk listeners reported hearing a load bang at approximately 12.40 BST.
One of them, Chris, said via WhatsApp: “The sonic boom scared the you-know-what out of me in Weasenham! The ground definitely shook.”
Gary texted: “Heard it in Cawston, door and windows rattled. Looked outside as thought a truck had crashed into the workshop next door.”
According to Flightradar24, the Air India jet was over the North Sea when it changed course and circled over Norfolk and parts of Suffolk several times.
By the time it was met by the RAF Typhoons, it was just off the Essex coast before continuing to its destination.
More than a dozen Indian flights have received hoax bomb threats since Monday, leading to long delays and diversions.
On Wednesday, an Air Akasa flight headed to Bengaluru city was redirected to the capital Delhi following a similar hoax.
Several Air India planes have been affected by these seemingly malicious false alarms.
In a statement, the airline said it was “extending all cooperation to authorities in identifying the perpetrators of such threats to ensure they are held accountable”.
A Royal Air Force spokesman said: “We can confirm that RAF Quick Reaction Alert Typhoon fighter aircraft from RAF Coningsby were launched this afternoon to investigate a civilian aircraft.
“Following an uneventful interception, the aircraft was released to continue to its original destination under the direction of civilian air traffic control. This incident is now being handled under the control of civilian authorities.”
The RAF said the Typhoon had been authorised to fly at supersonic speed for operational reasons.
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