Blues boss Alex McLeish has already signed Kevin Phillips from West Brom and wants to pair him up with Bent, while the Addicks will just be glad to get him off the wage bill.
A Cardiff statement read: "Shortly before Marcus Bent was due to arrive for his medical and complete his move to Cardiff City, we were informed that he had changed his mind and asked Charlton permission to speak to Birmingham.
"Whilst at this stage we are unaware of whether he has been given permission to talk to Birmingham City, we only want players who are committed to Cardiff City Football Club and therefore have withdrawn from the deal."
Charlton boss Alan Pardew is said to be lining up Bolton's Heider Helguson as a replacement.



