Birmingham acting chairman Peter Pannu has criticised Alex McLeish for walking away from the club and vowed the Scot will not be allowed to move on without a fight.
McLeish quit as manager in an email sent yesterday to Pannu, who was negotiating the signing of Danny Koevermans from PSV Eindhoven.
After agreeing deals for Marlon King, Chris Burke and Morgaro Gomis, Pannu was expecting McLeish to stay on at St Andrew's for Birmingham's first season back in the npower Championship following their relegation.
McLeish was instantly linked with a move across Birmingham to join Aston Villa as their new manager, a move unlikely to go down well with many supporters of both clubs.
Pannu was irked to see the former Scotland and Rangers boss depart, after he and owner Carson Yeung pledged their support in the wake of the drop from the Barclays Premier League.
Pannu said in the Daily Express: "I have just bought him [McLeish] three players of his choice.
"Having secured him the fourth one, Koevermans, I get an email on Sunday. It speaks volumes.
"We spent £40million, supported McLeish all the way, and what we get is a relegation and a snub when Carson gave him unwavering support."
McLeish had two years left on his Birmingham contract, and the club are expected to seek compensation for his departure should it be confirmed he has a job elsewhere lined up.
Pannu said: "He is still our contracted staff and Birmingham City FC does not grant him any right to speak to any outsiders until the matter is resolved. I'll be meeting my legal team tomorrow. It's about time discipline is instilled into this game and I am not a person who gets pushed about."
McLeish led Birmingham to Carling Cup final glory last season but their form in the Premier League dipped following their Wembley success, culminating in relegation after defeat at Tottenham on a dramatic final day of the campaign.