Well he left in the opposite direction he came so I think he was going the wrong way and wanted to turn around 
Ahh - so he was doing a (sort of) U turn - so,didn’t look in his mirrors or anything, was uncertain of where he was going, and suddenly decided he was going the wrong way!! Happens a lot - specially in London, where theres so many people who don’t know where there going.
But how the ferk is it not 100% his fault - if there was nowhere for him to turn into?