In roughly the late ‘60s, I am pretty sure before the Home Service became Radio 4, there used to be a serialised book reading each afternoon before the evening news. I remember “The Long Ships” by Bengtsson but there was another novel read at about the same time which I am at a loss to identify.
The plot has two story lines ( on the radio read by different people) which merge into the book's final sentence which was read by both readers simultaneously. It is possible that it is a murder novel, but this may be a red herring!
Sorry that this all I can remember!
Any help much appreciated
