Coventry City are hoping for a 20,000 gate on Saturday when they play Birmingham City at the Ricoh Arena (12.30pm kick off).
In addition, to the 4,000 Birmingham fans, City have sold 1800 tickets to scouts, cubs and guides from Coventry & Warwickshire, plus a thousand tickets through the Tickets For Schools programme.
Tickets for the game are on sale at the usual outlets.