Buhari Was Arrested in London? (SEE PHOTOS)

Was Buhari Arrested in London? What for? It seems it was after the chattam house speech. See photos below ... Governor Amaechi is seen at the far right of the video and Keyamo on the far left. Buhari with his traditional cap and white collar is seen at the middle.
Any one with more info on this (for eg why the UK police {"took"} them) should please share. See more photos below