We brought Morris home from the shelter a couple of months ago. Since then, we have not had any success getting him to wear a collar.
He's chipped, but will roam outside and we'd feel more comfortable if he had a collar on with ID.

His behaviour changes immediately, he hides, becomes despondent, gets aggressive and simply doesn't seem to be able to tolerate the collar. We've tried to force him to keep it for days, but his behavior deteriorates immediately.

Does anyone have any suggestions?

If you collar your cat and he goes outside,and it isn't a breakaway collar, you open him up to more dangers than are already out there. Collars get caught on fences, on branches, if they crawl under the house, they can get stuck underneath- I have so many emails from cat lovers who collared their outside cats and were sorry later.

If he is microchipped that is the best protection. Collars are easily removed anyway- some people will also have the vet tattoo inside the cat's ear for identification purposes.

http://www.mspca.org/site/pp.asp?c=gtIUK4OSG&b=127207

When I was looking at whether or not my cat should wear a collar I found this site which I found very informative. My cat now wears a collar. The article suggests giving your cat their favorite toy or cat nip when you first put the collar on. The idea is the cat will pay more attention to the toy and not notice the collar. It maybe worth a try. :)

If you collar your cat and he goes outside,and it isn't a breakaway collar, you open him up to more dangers than are already out there. Collars get caught on fences, on branches, if they crawl under the house, they can get stuck underneath- I have so many emails from cat lovers who collared their outside cats and were sorry later.

If he is microchipped that is the best protection. Collars are easily removed anyway- some people will also have the vet tattoo inside the cat's ear for identification purposes.
I agree! Also use cat write the id info on the collar... He may be afriad of the noise of a hanging charm.

You might want to try the Beastie Band style collars - they're very lightweight and soft, so my cats hardly notice them. They also stretch all the way around to release if they get caught on anything.

http://www.beastiebands.com/beastiebands.html