Oh no, that sucks. I'm lucky that I haven't had that problem ("knock on wood")

Few random thoughts about Christmas at our house-

We keep the presents locked away until Christmas morning. Under the tree invites them being ripped open or peed on.

Fortunately our house cats now are too old and fat to try to climb the tree. I the past we had a few who pulled it down. One solution was anchoring it to ceiling and wall. A bit extreme but it saved the breakable ornaments.

When the kids were toddlers I put the tree in a playpen for several years. Hey worked for us.

Thanks to everyone who replied. It's the same tree and decorations we have every year. He is always taken for a good run before we leave him at any time of the year. JodeeUK, no, I wouldn't leave small children alone with a tree on their own but Oz is a dog and dogs aren't welcome at Asda so I do have to leave him sometimes. It turns out that on both occasions he did damage, someone had come to the house. I'm now wondering if this got him excited and because no one came in he's done something for attention/frustration. I think we will have to start to get him used to staying in the kitchen, slowly at first then for longer periods till we can go out and leave him in there. It's back to basics again I think.