The Daily Mail says Ghaly, who had been at the club only four days with his £3million move from Tottenham still not finally sealed, complained about the training exercises he was being asked to do by manager Bruce.
After being told in no uncertain terms that he should join in with the rest of the squad during the morning session, he was ordered back for another dose of the same after lunch.
But he decided he did not want to be put through his paces again and Bruce blew his top. He ordered Ghaly out of the training ground - along with his agent - and told them in no uncertain terms that his move was off.
It could turn out to be an expensive mistake for the midfielder as he has blown a three-year deal worth £30,000 a week at St Andrew's.
A source said: "Ghaly told the manager that they didn't do as much running at Spurs as he had been doing this week at Birmingham. The manager was not very happy at all and asked if he meant Spurs' reserves? When Ghaly then voiced his dissatisfaction at a double session after lunch, it was the final straw."