This is the moment an unmarked military and police convoy stopped the traffic and stunned drivers and commuters as it swept through the city centre of Bristol this week.
The 14-vehicle convoy was captured on camera as it held up traffic on a main road into Bristol, and then headed out of the city on the M32.
The moment it came down the A37 Wells Road in Totterdown and joined the A4 Bath Road in a wail of sirens was captured by one surprised driver as she was waiting in her stationary car on the other side of the road.
The convoy began with a military police 4x4 car and then went on to include two police cars, three large police vans, another police 4x4, three large army people carriers and what appeared to be the subject of the guard of the convoy - four large LGV lorries with large unmarked containers on the trailers.
The brief video of the convoy was posted on social media within minutes of being spotted at around 7.50am on Wednesday, September 9 this week, and prompted a range of speculation as to what exactly was going on.
There was speculation that the convoy was operated by the AWE, the Atomic Weapons Establishment, an organisation which handles all the nuclear fuel for submarines and material for Britain's nuclear weapons.
The AWE is based at Aldermaston, at a base just the other side of Newbury in Berkshire. People commenting on the video, which went viral on Facebook, said they had seen many similar convoys around that area, but they usually took place in the middle of the night so did not attract attention.
It is unknown where this convoy had come from further south of Bristol, but heading to the M32 and then the M4 would fit with returning to Aldermaston.
One commenter said the operation could well have been a simple training exercise, or could have been a routine journey being made to refuel or return empty fuel from nuclear submarines.
Bristol Live contacted the Atomic Weapons Establishment, and a spokesperson declined to comment on the convoy, and said any inquiries should be made to the Ministry of Defence.
Bristol Live is currently awaiting a response from the MoD.
