Tilson worked to develop Southend's youth until the sacking of Steve Wignall in November 2003. With the club in danger of relegation to the Football Conference, Tilson was named caretaker-manager by chairman Ron Martin and proceeded to take Southend clear of danger. Also in the same season, Tilson led Southend to the first ever national cup final in the club's history, losing to Blackpool 2–0 in the Football League Trophy Final. In March 2004 Tilson was offered the job of manager on a full-time basis, and accepted the offer.