Ministry plate or vtg plate on trailer?

With regards to brand new trailers when does it become compulsory to have these fitted ?

Come on somebody must know.

DfT plates are fitted on trucks at first registration and on trailers after they have undergone a DfT annual test.

from

after a google search with this question

at what point must a new hgv trailer be fitted with a weight plate?

:smiley:

Strange that our trailers have the vtg plates fitted before the mot disc appears.