Know one believes me when I tell them about this programme. It was in the 60's, a group of people gathered round and told stories, which the others had to decide whether it was true or not. I am not LYING! honest
I remember it. I was allowed to stay up late on Saturday nights, and I think it alternated in The Avengers' slot. Regular stars were William Mervyn and Nyree Dawn Porter, and another one or two I've forgotten. IIRC they played various parts in mini plays, usually two or three per episode, all on the theme of lying.