According to legend, Christianity was brought to England by a small group of Christian refugees from Jerusalem. According to many versions the group included St. Joseph of Arimathea, Mary Magdalene and the Blessed Mother. The story goes that when the group landed on Glastonbury Tor, St. Joseph struck his staff into the ground before falling asleep for the night. When he awoke the staff had miraculously taken root and had grown into a tree.
The tree identified as that legendary staff was a focus of pilgrimages for centuries. It was famous for blooming twice a year, on Christmas Day and during Easter. It was cut down by Cromwell's Puritans during the English Civil War. The residents of the region however hid cuttings from the original tree, and the present tree was grown from descendants of those cuttings.
Given all that, it's not surprising that people in Glastonbury are in shock this morning after Thursday's discovery:
"The Holy Thorn Tree of Glastonbury has been chopped down in what is being seen by some as a deliberately anti-Christian act.
[...]Yesterday residents of Glastonbury wept as they surveyed the damage done to the tree on Wednesday night. Katherine Gorbing, curator of the town’s abbey, said: ‘The mindless vandals who have hacked down this tree have struck at the heart of Christianity.
A resident of Glastonbury describes the discovery yesterday:
[...]‘When I arrived at the Abbey this morning you could look over to the hill and see it was not there.
‘It’s a great shock to everyone in Glastonbury – the landscape of the town has changed overnight.’"
Much more and pictures here.