At a disciplinary hearing on Tuesday, Derbyshire claimed branch secretary Peter Moore was in breach of contract. He is a residential worker, on full-time leave for union duties.
According to Mr Moore, Derbyshire claimed the action was illegal because Unison, which represents the social services staff in Chesterfield who walked out, had not balloted staff beforehand. It also said Mr Moore had incited further illegal action.
Unison has disowned the walk-out. 'The action was repudiated by Unison, who had no alternative - the employer was threatening an injunction,' said John Freeman, Unison regional head of local government for the East Midlands.