The tree was over 70ft and would have required muscle and specialist equipment to chop down cleanly.

Someone holding a torch would have been needed to know where to cut. That suggests an accomplice.

The Sycamore also appears to have been cleanly sliced at the trunk - leaving behind a smooth stump.

Mike Pratt, chief executive of the Northumberland Wildlife Trust, believes a professional was behind the vandalism.

https://www.thesun.co.uk/news/24197547/three-clues-sycamore-gap-tree-cut-down-planned/ 

 @bade302b I wonder what the point of it was.. apart from sheer wanton destruction.