We tried various sized hacksaws.....the small ones were too small and the large one OH has was too big and awkward for me to handle. Plus the larger hack saw blades are usually painted and they leave paint residue on the bone.
The one I use is a fine tooth tenon saw, which has a reinforced top-edge, which stops the blade wavering when used.

You are right about the paint residue, when new, the ones I use are older and the paint has worn off.

Again you are right about a fine tooth tenon saw with the reinforced top edge, perfect, but your OH must love you a lot for him to allow such a fine tool to be used on bones I have several tenon saws including a Lie-Nielson which is made in America and cost me £143 and doesn't get loaned to anyone including my OH (I have often loaned her one of the other ones but never the Lie-Nielson)

I only ever use a hatchet, one good whack with a sharp hatchet and the bones cut, works well on frozen meat too.

Haha! Well I don't know about that but I'm pretty sure the saw he's given me for bones didn't cost that much!

I use a large, heavy Chinese hacker and whack the back ovvit wivvanammer.

I knew this would happen - so many different options! Thank you all for your suggestions; I'm thinking maybe a smallish hacksaw may the safest (for me and my worktops!) for the moment.

Ah - you see I do not whack bones and things on the worktop - I take them outside and put them down on the concrete to whack them!

Just make sure you use a plastic chopping board to cut it up on and the whole lot can go in the dishwasher afterwards.

Having nicked my hands and fingers many times chopping wood for coal fires in the past - I would not want to be using axes or blunt saws on a regular basis to cut bones.

My lighthearted response about what is good for cutting bones was going to be 'dogs' teeth' but I can see this is quite a serious subject so I won't say that!

I use a round of wood to do the chopping, I don't think I'd have a lot of kitchen left if I didn't lol.