How to train kitten to stop using litter tray and go outside!

[FeedMyFaceWithJaffaCakes]

Basically, we've had a cat flap for him which he loves, but he still comes in to have a wee/poo.
How can we train him to go outside?
X

They usually do it themselves. All the money we spend on covered trays for privacy and the end up going in the neighbours garden in view of everybody.

Don't. Why should your neighbours have your cat's shit in their garden?

Try putting it outside to see if it uses it there.

Where is your litter tray? Gradually put it closer to the cat flap door where the cat comes in and out and then put it outside on the other side of the door. They will usually decide to start going outside. Don't be shocked if there are a couple of accidents but most cats work it out very quickly in my experience.

Why do you want to? I agree with Apostrophe

If you live out in the countryside with no close neighbours, digging a fresh patch of soil for it to use may do the trick. However if you are in town or have smallish gardens / close neighbours then keeping the trays is the only responsible answer, you can get covered ones for outdoor use but not sure how you stop neighbouring cats using them.