Did David Cameron Disrespect Buhari In This Photo?

This is one part of the meeting between the President Elect of The Frederal Republic of Nigeria Gen. Muhammadu Buhari and the British Prime Minister David Cameron many Nigerians wouldnt want to see.
Before the meeting , Buhari was seen alone waiting for close to 30 minutes for before he had access to The Prime Minister who after the meeting ,walked the next Nigerian President to the door and promptly turned back and left. Leaving Buhari stranded