Sean Phipps, 51, was convicted of kidnap and rape in 2002, and has previously gone by a number of surnames, including Cawthray, Goldthorpe, and Perry.
He was on day release on Wednesday 1 June when he absconded and is believed to be in the Bristol city centre area. Members of the public are being urged not to approach him but call 999 instead.
Phipps is described as white, about 6ft 2ins and was wearing at the time of his release a black coat over a blue top, blue jeans and Timberland footwear. He also wore a black Casio watch, blue glasses, and carried a vape pen with him.
Detective Inspector Dan Rowan said: “Sean Phipps travelled to Bristol city centre on Wednesday but failed to return to HMP Leyhill as required.
“At this time we are keeping an open mind as to where he is, but believe he could have travelled outside the force area. He’s known to have links with the Leicester and Leeds areas.
“We’d please ask anyone who sees Phipps to call 999 and give reference number 5222130002.”