The 'traitor', Councillor Brian Brady, smiled as Labour colleagues urged him to resign. Twenty-four hours earlier, the recording Mr Brady had made was heard at an industrial tribunal.
The tape and the tribunal are the latest episode in a bitter struggle in Monklands, which has embarrassed John Smith, the Labour leader, whose constituency lies in the area near Glasgow. For two years, council leaders - dubbed the 'Monklands Mafia' - have failed to rebut allegations of corruption and sectarianism.
Mr Brady and disgruntled party workers accuse the leadership of nepotism, pointing out that 30 to 40 relatives of councillors, including the son and daughter of Jim Brooks, the council leader.
Figures showing that between 1989 and 1992 the council spent more than pounds 400 a head in the mainly Catholic town of Coatbridge and less than pounds 100 a head in mainly Protestant Airdrie, expose the leadership's sectarian bias, they claim.
In an interview with the Independent on Sunday, Mr Brooks said: 'The rebels are jealous of our success. They want to depose us and take over the council.'
He insisted that relatives on the payroll were 'well qualified and fairly appointed.' A decision to use green coloured forms for job applicants related to councillors and pink ones for the unemployed was 'purely designed to increase administrative efficiency'.
Records for the last 10 years, he said, showed that spending had been evenly distributed throughout the district.
But in the industrial tribunal in Glasgow on Wednesday, one of Mr Brooks's senior colleagues faced charges that the exchange Mr Brady had secretly tape-recorded revealed that the council had victimised 'troublesome' staff. A transcript of the conversation between Mr Brady and James Dempsey, director of leisure and recreation, revealed that Mr Dempsey was deeply concerned by a decision two years ago to sack a foreman called Tom McFarlane.
On the tape Mr Dempsey says: 'This man McFarlane . . . it's going to be a nasty one. He'll be going around to get support. I can't blame him . . . It's a totally embarrassing situation . . . I'll have to go to a tribunal. No way you could sit on a tribunal and tell a pack of lies . . . I expect that I'll be embarrassed . . . I've let the chief executive know I'm not happy about this.' He goes on to describe Mr McFarlane as 'a naughty boy'.
The tribunal heard that the decision to sack Mr McFarlane was taken by three councillors, including Mr Brooks, in a 'corridor meeting'. No minutes could be found.
Mr McFarlane, 52, alleges that Mr Dempsey's comments prove that he was sacked because, three months earlier, he had called for the resignation of a local Labour official who, he said, had manipulated a shortlist of candidates for local elections.
Councillors, he said, had hire and fire powers and 'if you didn't agree with them or their cronies in the local Labour party you were earmarked for the dole.'
Mr Dempsey told the tribunal he 'could not recall' why he had described Mr McFarlane as a naughty boy. He denied that the expression referred to criticism of Labour officials and insisted the decision to sack him, at a time when the council had a no-redundancy policy, was part of a 'rationalisation programme'.
The tribunal will give its ruling later this month.