Leo Slater was the fiancé of Lillian Smith after her divorce from Dave Smith in 1969. He had a nefarious past and was referred to as a villain by policeman Cyril Turpin, who recognised him upon his arrival in Weatherfield in September of that year, to meet Dave so that Dave would agree to a divorce from Lillian. Leo nearly always wore a suit and fedora and charmed his way into people's affections, but he met his match in Dave, who was courteous but suspicious of him. When Dave found out about a particular incident which cast doubt on Leo's character, he discussed it with Leo and Lillian and upon finding out Lillian was fine with it, he granted the divorce.