Hamer was an alcoholic, who by the time of his last film as director, School for Scoundrels (1960) was "often battling terrifying DT hallucinations" (i.e. alcohol withdrawal symptoms, occurring only in patients with a history of alcoholism). BFI Screenonline writes that Hamer was "a recovering alcoholic" and that "he fell off the wagon during production [of School For Scoundrels], was sacked on the spot ... and would never work in the industry again." Hamer was also homosexual in an era when it was illegal in the UK. He. died of pneumonia at the age of 52 at St Thomas's Hospital in London, and is buried at Llandegley.
Hamer's career "now looks like the most serious miscarriage of talent in the postwar British cinema", according to film critic David Thomson.