Chock-A-Block was a BBC children's television programme, first shown in 1981 and repeated through to 1989 and shown as part of the children's programme cycle See-Saw (the "new" name for the cycle originally known as Watch with Mother). "Chock-A-Block" was an extremely large yellow computer, modelled to resemble a mainframe of the time; it filled the entire studio and provided the entire backdrop for the show. The presenter of the show supposedly played the part of a technician maintaining the computer; there were two presenters, Fred Harris ("Chock-A-Bloke") and Carol Leader ("Chock-A-Girl"), but only one appeared in each episode. At the start of the show, they would drive around the studio towards the machine in a small yellow electric car (with the catchphrase "Chock-A-Bloke (or Girl), checking in!").
The presenter would then use the machine to find out about a particular topic. The name "chock-a-block" was supposedly derived from the machine's ability to read data from "blocks" - which were just that, physical blocks painted different colours. A typical show would include dialogue from the presenter, a brief clip played on Chock-a-block's video screen, and the presenter recording a song on Chock-a-block's audio recorder (which resembled the reel-to-reel tape drives used on actual mainframes, but with a design below to cause the reels to resemble the eyes of a smiling face).