Bruce will take his current club to St Andrew's on Saturday and remains bitter about the manner in which his six-year spell at the Blues concluded.
The 48-year-old's departure came at a time when Birmingham were subject to a failed takeover bid from Carson Yeung. Ironically, this weekend's match will be Yeung's first home fixture since his successful purchase of the club earlier this month.
"I was left in an impossible situation and nowhere to go really," Bruce told BBC Radio Five Live.
"It was becoming a soap opera. [I wanted to know] what we are going to do for the future of the football club. We had just got back up and there was no mention of the team or what we were going to do about the team and about players.
"It was just about the takeover of the club. I was left in a situation where promises were broken. To be fair Mr Sullivan [David Sullivan, the then co-owner] wanted to give me a new contract, then all of a sudden it became an issue with the board. It was an ongoing saga. It became impossible to manage. In the end I had to go."