difference between leave winning over remain was just a few percentage points. and almost 2/3 of a million pounds makes all the difference. and it wasn't legal. >> reporter: now that's a drastic conclusion. but here is what sanni alleged. it hit its legal spending limits so it gave the surplus to youth activists who they behave believe gave to it canadians for digital advertising that is illegal sanni and some legal expert says if there is coordination with the leave campaign. sanni says e-mails and shared drives prove coordination. believe campaign deny any wrongdoing and say they got electoral watchdog permission to pass it on. uk elected officials say they haven't said what they conclude of the evidence. all this really exposes is how poorly equipped british campaign finance law is along with those who are meant to enforce it.