Birmingham City co-owner David Sullivan admits they rejected big money for some of their best players during last month's market.

"We're very, very frustrated that we haven't been able to help the manager more," said Sullivan. "There were loads of deals we were juggling, but they didn't all fall into place.

"Believe me, it was not for the want of trying.

"Personally, I have never worked so hard in my life to achieve so little. Its been the most difficult time I've ever known to persuade players to come to Birmingham City.

"We went the extra mile for Gary Cahill, but he chose to go elsewhere.

"The Tottenham player [Teemu Tainio] was all a bit rushed really and he wanted a massive rise in salary.

"It's been very, very hard bringing people in, but we have faith in the squad and then in the summer we will strengthen and shake it up in the summer with a few ins and outs.

"We believe the players we have got in will improve the team, and we were very disappointed and surprised when we were refused a work permit for the Georgia captain [Levan Tskitishvili].

"We had a lot of clubs come in for our players as well this transfer window.

"We allowed some to move but on others we wouldn't do business.

"We turned down £7 million, and £5 million for another.

"You'd think about the offers and then wonder where would you actually get better if you let them go."