Trailer ABS fault

Abs fault is only an advisory on MOT

Trailers prob 8-10 years old ,Kraker ?walking floor galvanised chassis tho , so in good condition . No tps , I certainly didn’t realise abs fault was advisory only ! So what happens if pulled by vosa ,surely it’s a delayed prohibition ? Which means getting it fixed and back to mot station ?
I know if I have an abs light on for my car mot it’s a fail now ?