He joined Widnes in August 2020, replacing Craig Davies, who left the club to take up the managerial position at Prescot Cables.
Dempsey had previously managed Ashton Town up until December 2019, having guided the club to promotion back to the North West Counties from the Cheshire League in 2018.
The club have also confirmed that striker Daley Woods has also left the club to join up with Dempsey at Ashton in a player/coach capacity.
Keep up-to-date with our exclusive email newsletters.
Subscribe