Charge after WA prisoner attacks inmate

A 19-year-old prisoner has been charged after another inmate was attacked at Bunbury Regional Prison in WA's south, leaving the 42-year-old with life threatening injuries.

The victim was assaulted about 9.40am on Saturday and admitted to the intensive care unit at Royal Perth Hospital, where he is in a critical but stable condition.

His alleged assailant was charged with grievous bodily harm on Tuesday and is due to appear by video link in the Bunbury Magistrates Court on Friday.