Letterbox in the UK? [PAL TV system]

There are three basic approaches to the transmission of a 16:9 aspect ratio image using the PAL system: the `letterbox´ method, the `side-panel´ method, and a compromise letterbox approach sometimes referred to as a `window´ method. Each has particular advantages and disadvantages. It will be shown that the UK terrestrial broadcasters consider that there would be advantages in being able to choose to transmit some programmes, for a temporary period only, in a compromise letterbox format, as a means of easing the introduction of PALplus, which uses a 16:9 letterbox