An expert claims the loud bangs which baffled Britons last night sounded like a type of experimental jet engine – which conspiracy theorists enjoy linking to a rumoured spy plane.
Dr Bhupendra Khandelwal added his comparison to a debate which began when hundreds of Twitter users from Aberdeen to Devon – and even New York – reported ‘explosions’ which shook windows and disturbed sleeping children at around 10pm.
‘We can’t say for sure what this sound was,’ he added. ‘It’s possible, but even if it was a PDE, I think half an hour would be a bit too long!’
Steven Aftergood, a government secrecy expert at the Federation of American Scientists, said: ‘If an aircraft is responsible, then it’s worth noting that it may not be local at all.
‘Because the sound wave that causes the boom can be reflected by the stratosphere, the source of the event could conceivably be hundreds or thousands of miles away from the place where it is heard on the ground.’
Listen to the Audio Recording of the Booms:
But Dr Andrew Taylor, a senior lecturer in aviation at Buckinghamshire New University, said the noises did not sound like a normal sonic boom.
‘With smaller fighter jets just a single boom would be heard, or, as with Concorde, a “double boom” might be heard from larger aircraft as both the nose and tail cause shock waves,’ he said.
‘It sounds like gunfire or other ammunition, similar to what I used to hear as a child growing up in Lincolnshire when the RAF & USAF aircraft used to do bombing runs on the east coast bombing ranges.
‘It could be geological or meteorological, but certainly not aeronautical in my opinion.’
Many Twitter users suspected sonic booms, similar to ones which shook Kent last month when two RAF jets intercepted a Latvian cargo plane in British airspace.
But a Ministry of Defence spokesman told MailOnline last night she had no records of any jets being scrambled.
Some suggested unusual weather conditions might be the source, but the Met Office dismissed those claims and said there was nothing out of the ordinary.
A spokesman told MailOnline: ‘It definitely wasn’t meteorological’.
The Metropolitan Police said there had been a fireworks display in Croydon, but Twitter users insisted that could not explain sounds in Bedfordshire, Glasgow, North Devon, Leicestershire and West Sussex.
At around the same time, a loud boom was reported by a number of people in the upstate New York areas of Buffalo, Cheektowaga and Clarence more than 3,000 miles away.
People described it as loud enough to shake their homes and rattle windows.