I work in a very small team and, in the past few days, the most senior has been told he is being demoted. Today, he decided to tell my colleague (who is on a similar level to me) that I am paid a few grand more than them. They are understandably upset. It does seem that he said this to cause trouble and friction between us (he has form for this, one of the many reasons he is being demoted/ redeployed) as, when I questioned him to the motivation behind him disclosing this, he had no valid reason.
Has there been a breach in confidentiality? Can I log a formal complaint against him for disclosing confidential information?