A large bang heard by hundreds of people across Britain on Thursday was caused by two Typhoon aircraft responding to an emergency, the UK Ministry of Defence said.

The RAF jets were on their way to a small civilian helicopter that had emitted an emergency signal on a frequency it should not have been using, but the error was realised too late.

An MoD spokesman said the fighter planes had been author-ised to go supersonic and were already on their way to the helicopter.

He said: “We can confirm that a small civilian aircraft was transmitting inadvertently on an emergency frequency at approximately 6.10 p.m. “Two typhoons from the Quick Reaction Alert responded accordingly and authorisation was given from them to go supersonic, which resulted in the sonic boom.

“There was no actual threat to the civilian aircraft and they soon rectified their mistake.”

A sonic boom is the sound associated with the shockwaves created when an object travels through the air and breaks the sound barrier.

The noise contains large amounts of sound energy, meaning sonic booms are often mistaken for explosions.

Reports of the sonic boom came in from Bath, Swindon, Coventry, Rugby and Oxford.

Speculation about what could have caused the noise ranged from a large explosion to an underground tremor. It is the second time this year that a sonic boom has been created by a Typhoon aircraft.

In January, the MoD confirmed that a loud noise heard by people across the North of England was caused by an RAF fighter jet breaking the sound barrier. Dan Cross, bar and restaurant supervisor at Millsy’s in Earlsdon, Coventry, said the noise was so forceful it shook the walls of the restaurant.

“It sounded like it was coming from the kitchen,” he said. “I thought somebody had dropped one of the big ovens in there. It was a really loud bang and the room shook and all the wine glasses on the rack shook.

“When it wasn’t coming from the kitchen I thought maybe it was the cellar, but then wondered if it could be something else. It was weird, but didn’t last long.”

Jennifer Lawlor, a supervisor at the Spar shop in Daventry Road, said she did not experience anything but her boyfriend, Martin Ward, rang her and told her the walls of his house were ­shaking.

“He said there were two very loud bangs and he felt the room was shaking,” she said.

The jets were scrambled because the frequency the helicopter pilot mistakenly transmitted on is only used when an aircraft is in particular trouble.

Such a signal could indicate the aircraft had been hijacked or had “gone rogue”.

The world’s most advanced combat plane

• Britain’s Typhoon fighter jet is an agile, single seat, multi-role aircraft built for high-altitude supersonic air combat and formidable ground attack capabilities.

• Dubbed the eurofighter, it was designed and built by a four-nation consortium consisting of companies from the UK, Germany, Italy and Spain at a cost of over £30 billion.

• The Typhoon is the world’s most advanced new generation multi-role combat aircraft. It entered service with the RAF in 2003 gradually replacing the existing Tornado F3.

• It serves in five of Britain’s front-line squadrons and is currently employed on permanent ops in Falkland Islands and patrols the UK.