 Many systems were installed in the UK including the world's first supermarket teleshopping system.Nearly all books and articles (in English) from videotex's heyday (the late 1970s and early 1980s) seem to reflect a common assumption that in any given videotex system, there would be a single company that would build and operate the network.Although this appears shortsighted in retrospect, it is important to realize that communications had been perceived as a natural monopoly for almost a century — indeed, in much of the world, telephone networks were then and still are explicitly operated as a government monopoly.