Northern Ireland police ombudsman Nuala O'Loan had a stand up row with senior Democratic Unionist Party member, Ian Paisley Junior, in a Belfast city centre coffee house, it was revealed las night.
The pair clashed in front of customers, with the argument understood to have centred on Mrs O'Loan's family.
The police ombudsman was with two of her sons when a tense exchange rapidly escalated yesterday afternoon.
At one stage it is believed Mr Paisley, a member of the Northern Ireland Policing Board and a fierce critic of Mrs O'Loan, asked one of her sons to leave the premises.
The DUP Assemblyman had been in the cafe with an official from the Northern Ireland Office when the row flared.
One onlooker said: "The whole place went silent. It was totally unbelievable."
A spokesman for Mrs O'Loan confirmed there had been an incident, but emphatically denied that either of her sons had hurled any abuse.
He said: "The two of them (Mrs O'Loan and Mr Paisley) encountered each other in a coffee house and got into a discussion.
"It's understood Mrs O'Loan was talking about Mr Paisley's views on the Office and other matters relating to her children.
"The son didn't shout anything and although it was a heated discussion it was simply that and nothing more."
PA