Members of Brent LBC's ruling Tory group have requested a committee report on the relative merits of derecognising the union, following an exchange of letters between chief executive George Benham and Greater London Unison regional official Stuart Barber.
Mr Barber last month made detailed allegations of financial mismanagement in the council's social services department.
But, in a response sent to Mr Barber last week, Mr Benham angrily dismissed the claims as a 'farrago of misinformation' and warned: 'Derecognition of Unison is now a political issue in Brent.'
But Mr Barber this week hit back at Mr Benham's 'hypersensitive' response and claimed the council had mounted a 'dirty tricks' campaign against him and his union. He called on the chief executive to withdraw a specific remark contained within his letter or 'I will obviously have to consider further action against you'.
Brent social services and housing chairman Irwin Van Colle told LGC: 'We prefer to get on well with the unions. . . The local officers we don't have a problem with. But Mr Barber seems to be going out on a limb in the way he doesn't like negotiating with us.'
Of Mr Benham's 'derecognition' comment, Mr Van Colle said: 'The officers are entitled to take a view. They deal directly with the union.' He added: 'It may be in their (Unison's) interests to find someone else at regional level to deal with us.'
Brent Unison branch secretary Brian Butterworth denied his union enjoyed good relations with the authority and said: 'Stuart beavering away has embarrassed (the council) considerably.' He claimed Brent had been engaged in a process of 'de facto derecognition' through unilateral downgradings and job reassessment.