A loud bang heard across a large part of England was from a sonic boom caused by a Typhoon jet, the Ministry of Defence has confirmed.
Police and fire services in the West Midlands were inundated with phone calls shortly after 6pm from concerned members of the public.
Many people on Twitter and other social networking sites confirmed they had also heard the noise, some as far as Swindon and Oxfordshire.
A spokesman for the Ministry of Defence confirmed the bang was caused by a Typhoon fighter aircraft.
The plane was one of two Typhoons that had been launched following an emergency call from a helicopter.
The helicopter had transmitted on the wrong frequency, the MoD spokesman said.
Residents, mainly in the Coventry area, said they had heard a gigantic bang which police initially suggested was down to a minor earth tremor.
However, the British Geological Survey told Sky News it had no seismic records to indicate a tremor had struck.
Theories abounded on Twitter, ranging from bomb blasts to giant earthquakes.
The reports were retweeted by thousands of people and the incident rapidly became one of the site's largest trending subjects.