For him to be sacked it either means it’s serious OR he’s breached employment conditions. Possibly both.
If he has a clause in his contract about disclosing in full past matters that may bring the organisation into disrepute and he has not declared this in full then per is contrat it would likely be gross misconduct.
He doesn’t need to have been to court and found guilty for his employer to dismiss him in that basis as long as they have followed their correct internal procedures in doing so.
it’s been said earlier in the thread but the criminal law aspect is separate to employment terms.
Anyway, regardless of exact circumstances, it seems like the BBC have learned to pull their finger out and act. At last!