They're bastardising 4:3 source material on UK tv nowadays, cropping it to some weird 'widescreen' format that isn't quite 4:3 and isn't quite 16:9, so on a 4:3 tv you get thin black bars on the top/bottom but on a widescreen tv in 4:3 non-zoom mode you get the same thin black bars but also big black bars on the sides too! and if you put the 16:9 tv in zoom mode it fills the screen but crops some of the top/bottom of the picture.

So if you're watching the 4:3 material they cropped to their strange 'widescreen' format on a widescreen tv in zoom mode then you're missing out on the top/bottom and sides of the original picture!