Allen was convicted in relation to murder following an incident in June 2008 and has since breached the conditions of his temporary prison release.
He is described as being approximately 5 ft 11 ins in height, of medium build, and has a fresh complexion. He has blue eyes, dirty fair hair, and scars on his right hand, his left finger, and his knee.
Despite attempts to arrest Glen Allen, police have so far been unable to locate him.
Police are appealing to anyone who has seen him, or who knows of his whereabouts, not to approach him, but to contact police on 101 quoting reference 1452 of 14/12/22.
Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous.
Police would also appeal directly to Glen to hand himself in.
