Wagstaff, aged 34, was serving an indeterminate sentence for robbery when he absconded from Hatfield prison at 8.10pm on Monday, January 10.
He is white, and described as being of medium build, around 6ft tall with short cropped brown hair.
Wagstaff has a scar on his left hand and a tattoo saying ‘Leah’.
Police ask, if you see him, please do not approach but instead call 999 immediately.
The incident number is 798.