Danval, read an earlier post, some cats cannot be contained in that manner, it does not suit their personalities and their behaviour becomes intolerable. Take him to the vet and have him put down then I hear someone suggest, try getting a vet to put down a cat that isn't dying - they won't do it.
If I had a cat that liked to be inside all his life, I would do as BBP does too, but you just don't know what sort of cat you will get unless you have it from kittenhood and it's been raised well that far. Some cats like to go out, some don't. Even if you get a well behaved cat it still behaves as it pleases.
One neighbour's cat had a bell and he learned to become even more stealthy and still catch birds.
I think that is the major difference between owning a cat instead of a dog, and people who don't love cats don't seem to get it. Part of the reason we like cats is because they are their own bosses, they do as they please and are independant. We like to have an animal that is supposedly free to go but still comes back because it makes us feel good. No doubt the haters will use this information to criticise further but that is the fact.