A little V cut with a chisel:
Looks like there is still living tissue there. Don't know why it didn't sprout this spring. I don't like the position of the leader anyway, maybe I can salvage it and get it positioned better with a graft. I'm going to give it a go before I cut it to a lower leader.
Expose the cambium on the sides (probably completely useless on a green spring shoot), but I did it anyway.
And remove the cambium on the side of the shoot facing the tree. This is important - you don't want growth on that side as it tends to force the graft out of the V cut. So suppress it on that side by removing more of the growing tissue. On lignified wood it's easy to tell when you get through the cambium. On a green spring shoot? No clue, but I tried removing more of the tissue on that side of the shoot.