The great "ripping" noise was a very large Beech tree splitting in half, just inside the entrance to my local park (about fifty yards away).
They were cordoning it all off as I came back out about fifteen minute ago...
The main trunk is now at 45 degrees, leaning against an adjacent beech.
Hundreds of schoolkids pass through there every day, so it's wise that they've stopped them from walking underneath, the way things are...