Harford was linked with a move to Swindon a few weeks ago, but it didn't happen then because of problems with his contract at Nottingham Forest.
Harford who is said to be best friends with Andy King will now become his number two after Mike Walsh left the club a few weeks ago by mutual consent. Harford attended today's training session, and meant the players.
Harford said: "The situation is that Andy is a very good friend of mine and this is a good opportunity to come down and work with him until the end of the season."