Topband: Non-Invasive tree attachment?

[Tracey Gardner]

I'm replacing my Beverage and want to tension the wire at the far end by fixing it to a low horizontal branch of a large old willow tree.
The branch in question is substantial and about 9 inches in diameter.
I don't want to fix into the tree as it is not my tree.

Can anybody suggest a suitable non-invasive means of making an attachment?

Many thanks

Tracey G5VU