Beckham's willingness to enter negotiations about individual salary with Nottingham Forest was kept strictly confidential by Twain's order. No one else knew except for the Beckham couple, his agent and the three heads at the Forest team, as well as Twain's close friend, Dunn. Even Real Madrid did not know about it and still used insulting terms to drag their feet on the "tough" negotiations for the contract extension with his agent.
On the one hand, it was not December 31st yet, and Beckham's contract with Real Madrid was still in effect. The other clubs could not contact the players in private. Otherwise, if Real Madrid found out, it could be taken to FIFA, and then it would create a mess.
In addition, Twain did not want to give other competitors the opportunity to intervene. As far as he knew, there were three clubs in England that had made it clear they were interested in Beckham.