Statement from the Metropolitan Police Federation following the death of Harry Roberts.
Roberts shot dead three unarmed officers who approached him and accomplices who were planning a robbery in 1966.
He was freed from a life sentence in prison 11 years ago.
Matt Cane, General Secretary of the Metropolitan Police Federation, said: “The three officers murdered by Roberts never got a chance to grow old.
“The life sentence for their loved ones still continues.
“Life should mean life if you murder a police officer in the course of their duties - Roberts should never have been freed."