A production supervisor from the north-east Worcestershire town of Redditch is seeking compensation over alleged constructive dismissal.
Mark Bayliss accuses his former employer of wanting him out of his job and of unfair treatment, the Redditch Advertiser reports.
He had worked at heat exchange firm Thermex for 26 years before he left.
According to the 47-year-old, his employers victimised him to such an extent that he became ill and required time off on sick leave.
He was off work for two months and did not return prior to his departure from Thermex, eventually resigning and claiming constructive unfair dismissal.
The man who had worked under Mr Bayliss was given his job after he left the organisation.
However, the company denies that it wanted him to leave or that it had victimised him, saying it had held the former worker in high regard.
A decision regarding the case is expected later this year.