Tottenham cannot sign Portsmouth striker Jermain Defoe in January.

It has been revealed that Premier League rule L19 says a player cannot return to his former club within 12 months of leaving.

A spokesman said: "It is written in section L19 of the Premier League rules that a club which transfers or cancels the registration of a player may not apply to register that player within a year.

"The only exception to that is if it has been made with the prior written consent of the Premier League board."