Birmingham have rejected an improved £6m offer from West Ham boss Alan Curbishley for defender Matthew Upson.
Upson has attracted plenty of interest from Premiership scouts
Upson, 27, has been watched by several Premiership clubs after a series of impressive displays for the promotion-chasing Championship side.
Blues turned down a £4m bid from West Ham and Curbishley has been snubbed again after increasing his offer.
Upson rejected a new five-year contract last season and his current deal expires at the end of the season.
He was again outstanding as the Blues thrashed Newcastle 5-1 in their FA Cup third-round replay.
But Blues boss Steve Bruce has insisted he is under no pressure to sell any of his key players during the January transfer window.
He is keen to hold on to the former Arsenal player as his team look to bounce back into the top flight after last season's relegation.
Upson made his comeback at the end of November after seven months out with an Achilles tendon problem and his return to action coincided with a tremendous run of form for Birmingham.
Curbishley has already signed Tottenham central defender Calum Davenport and Lucas Neill from Blackburn.