I was taking photographs of bees around a tree in my garden, in Kent, this afternoon. These were small, dark, probably solitary bees and they were quite active. I then noticed a red bee, or that was what I think it was, probably a mining bee, which landed on the branch. I managed a couple of shots of this red insect and then decided it was a bit distant for my macro lens, so I moved in to about twelve inches and was just focusing when one of the other bees attacked it, landing on its back, whereupon they both fell down towards the ground and out of my sight.
When I examined the photos on the computer I could see the red insect and the aggressor bee in both the shots.