West Ham United may make a formal complaint against Tottenham over their bid for Scott Parker.
The Daily Star says Hammers chairman David Sullivan believes Spurs made an illegal approach for the midfielder.
Sullivan insists Tottenham were aware that Parker was not for sale and that their offer was an attempt to unsettle him. Spurs boss Harry Redknapp strongly denied that accusation after his side's friendly defeat to Spanish side Villarreal on Thursday night.
However, West Ham are furious that their London rivals went ahead with a bid despite being told to back off. Parker has remained tightlipped about his future, but is understood to be tempted by the lure of Champions League football at White Hart Lane.
