Are you allowed to ride a 125cc motor scooter in the UK with just a provisional License, Tax, and insurance?

Or are there any compulsory tests that you have to pass before you are legal on the road.

Theory test and a CBT (compulsary basic training) you'll have to do the later through an approved riding school, you've also got to be a minmum of 17 years old to ride a 125cc.
You also have to have a provisional catergory A entitlement on your license.

Yes, but in England you have to do a basic test but not in northern ireland

yes you have to do compulsory basic training to ride with L plaits

yes but it must be less than 12 B.H.P

I think you have to by law do a CBT.

No.

If you have a full driving licence with provisional motorcycle entitlement, you can ride up to 50cc without any compulsory tests.

However, if you want to ride anything above 50cc, or you don't already have provisional entitlement from a driving licence, then you *have* to be over 17 (you can ride a 50cc at 16) and you have to take a CBT (compulsory basic training) before you're allowed on the road.

You have to renew your CBT every two years until you pass your test.

you cant ride any size motorcycle without first passing a CBT (compulsory Bike Training) test which then allows you to ride anything up to a 125 with L plates i believe

You have to take a CBT course, and PASS first

as long as you have a cbt pass certifcate you can