They withdrew a promotion after I completed the training
I've been employed by my current employer for 5 years. Last year I was selected for a management training programme that was described as preparation for promotion. I completed the programme over eight months, including additional work outside my normal hours.
I was told that once a vacancy became available, I would be promoted. A vacancy has now opened, but management have instead advertised it externally and offered the role to someone with no experience in the company. I have emails stating that I was accepted onto the programme because it was intended to prepare me for promotion, but nothing explicitly guaranteeing the role. Do I have any legal grounds for breach of contract, detrimental reliance, or anything similar, or is this simply unfair but lawful?