Royal Air Force fighters had to intercept a civilian plane that reported a bomb on board.
The Air India aircraft circled over Norfolk before the Typhoon interceptors encountered it.
An RAF spokesman said the alert ended without incident and the Boeing 777-300 “was released to proceed to its original destination”.
The plane landed safely at Heathrow Airport some time later.
Audio of the passenger plane crew warning air traffic control of 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, which requires a priority landing.”
It continued: “We have a bomb threat. Air India 129 requesting descent.”
The aircraft enthusiast, who could only be recognized by his X username, @EHEH_spotter, confirmed to the BBC that he had made the recording with a scanner.
A loud sonic boom was reported across Norfolk as the fighter jets rushed to intercept the aircraft.
BBC Radio Norfolk listeners reported hearing a crash at approximately 12:40 BST.
One of them, Chris, said via WhatsApp: “The sonic boom scared the hell out of me at Weasenham! The ground absolutely shook.”
Gary texted: ‘I heard it in Cawston, the door and windows rattling. Looked outside and thought a truck had crashed into the workshop next door.’
According to Flightradar24, the Air India plane was over the North Sea when it changed course and circled several times over Norfolk and parts of Suffolk.
By the time it was met by RAF Typhoons it was just off the coast of Essex 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 bound for Bengaluru was diverted to the capital Delhi after a similar hoax.
Several Air India aircraft have been affected by these apparently malicious false alarms.
In a statement, the airline said it was “fully cooperating with authorities in identifying the perpetrators of such threats to ensure they are held accountable.”
A Royal Air Force spokesperson said: “We can confirm that RAF Quick Reaction Alert Typhoon fighter jets from RAF Coningsby were launched this afternoon to investigate a civilian aircraft.
“After an uneventful interception, the aircraft was released to continue to its original destination under the guidance of civil air traffic control. This incident is now being handled under the control of civil authorities.”
The RAF said the Typhoon had been cleared to fly at supersonic speed for operational reasons.
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