RAF Typhoons escorted the Air India aircraft to London Stansted (Picture: Lee Plama/Twitter).
An Air India passenger plane has made a "precautionary landing" at London's Stansted Airport due to a security threat.
The flight, AI191, was on its way from Mumbai, India to Newark in the US.
The Ministry of Defence said RAF Typhoon planes escorted the aircraft as it made its landing.
Air India initially reported a bomb threat, tweeting that this had prompted the landing, but later deleted the tweet, calling the incident a "security threat" instead.
A statement from Stansted Airport said the plane landed at about 10:15 BST and was now in an isolated part of the airport - and the main terminal was unaffected.
Derbyshire Police tweeted: "If you heard a loud bang over #Derbyshire today, this was as a result of a @RoyalAirForce jet passing over that caused a sonic boom."
Stansted said its runway was briefly closed to accommodate the landing of the Air India plane, and that it had since reopened.
"We are very sorry for any delays and disruption caused by the incident, but our first priority is always the safety of passengers and staff," Stansted Airport said on Twitter.
It was not known how many passengers were on board, the airport said.
An RAF spokesperson confirmed that "Quick Reaction Alert Typhoon aircraft were launched this morning from RAF Coningsby to intercept a civilian aircraft":
"The aircraft was safely escorted to Stansted airport.
"The Typhoon aircraft were authorised to transit at supersonic speed for operational reasons; any inconvenience caused to local residents is regretted.”
Many on social media reported a loud boom being heard due to the supersonic speed of the jets.