White collar workers at the Corporation of Hamilton have issued a 21 day strike notice, The Royal Gazette has learned.The development is an escalation of a months long dispute between the City Council and its managers who have accused Mayor Graeme Outerbridge and his Council of unfair labour practices and interfering with the staff’s trade union rights.The Bermuda Public Services Union filed a formal complaint with the Labour Relations Department in November last year.The City leaders were accused of attempting to vary or nullify the rights of workers and managers to belong to the union of their choice, and of executive managers and managers to bargain collectively.Other claims included a failure on the part of the Mayor and the Council to respect “the importance and confidentiality of executive managers/managers’ job descriptions that form the contractual relationship between the Corporation as the employer and the employee or the union”.The complaint letter warned that discussions on the duties of managers must occur with them and “not third parties”.City leaders were also accused of providing “ambiguous, varied and mixed instructions to managerial staff contrary to the code of conduct which sets out good governance practices for the employer and employee concerning the day-to-day running of the Corporation”.“The City of Hamilton Council is aware that action has been taken by the BPSU,” said Mr Outerbridge in a statement.“We are working to resolve our differences in a constructive manner. In the future, we will not elaborate on this issue in the media.”It is understood that the strike notice was sent to the Labour Relations Department yesterday afternoon.The Corporation employs about 170 workers. About half a dozen of them are professional or managerial staff and represented by the BPSU. The rest are represented by the Bermuda Industrial Union.