Orb UAP videoed in UK darts and accelerates into the clouds

What looks like at first another possible balloon sighting starts to get interesting around 25 seconds in.  The sphere / orb UAP starts to behave unlike a balloon and quickly darts around and changing directions before it zooms off.

Food for thought: Most videos like these are taken with a cell phone which in turn can act as a homing beacon to anything with sophisticated instruments that can detect the videographer’s presence and speed off.

Source 1

Source 2

What do you think it is?