A senior police officer's suggestion of mitigating circumstances for drink driving officers keeping their jobs has been labelled "absolutely obscene".
Constable Donnelly was banned from driving for 12 months
He said drink driving was wrong, but raised hypothetical situations in which those facing disciplinary proceedings could claim justification.
Deputy Chief Constable Paul Leighton also defended allowing an officer caught drink driving to retain her job.
He said the incident preceded the PSNI's dismissal policy of May 2006.
Constable Geraldine Donnelly was edited out of a TV ad after the offence.
The ad had been to warn about the dangers of drink and drug driving.
The constable is now back at work despite pleading guilty to the offence, being fined £120 and banned from driving for 12 months.
On Thursday, Mr Leighton said she had not been sacked because the incident pre-dated his vow to dismiss officers caught drink driving.
In May 2006, Mr Leighton warned any officer caught breaking the law would be sacked or forced to resign.
Mr Leighton told the BBC's Nolan Show: "I am not going to hypothesise about issues in cases in court where someone has maybe had a glass of wine and someone takes ill in the household and there is no ambulance available and they rush someone to hospital.
"Those are hypothetical circumstances, but those are exactly the type of circumstances that must be allowed for in any process."
He added: "Since we made our policy statement in May 2006, any case post that date that has come to hearing, the officer has been either required to resign or has been dismissed.
"That is not to say that there may not be a case where there are mitigating circumstances that allow a tribunal to allow that officer to remain in post."
Deputy chief constable Paul Leighton said she had not been sacked
However, David Lyle, the chief executive of the company which made the TV ad, said there could be no mitigating circumstances in which someone could drink and drive.
"It is just absolutely obscene that anyone should try to justify a situation where it is possible to have some drink and drive - it is dangerous to members of the family and members of the public."
Mr Lyle, head of Lyle Bailie International, said any member of his company disqualified for drink driving would be automatically sacked.
He said the fact that this did not happen within the PSNI needed to be examined by the Policing Board.
"We are deeply embarrassed by this situation and I'm sure all the dedicated police officers who helped us over the years in making these ads and appeared in them, are deeply embarrassed."
The issue is expected to be discussed at the next Policing Board meeting.