That's funny. Someone in London/Leeds has presumably flipped the switch that gives STV control over their pictures and left them to it. STV could theoretically broadcast anything here and they wouldn't notice.
The usual reason for the match not being in widescreen AFAIK is because the host country aren't broadcasting it in that format, although you'd think Spanish television would be far enough advanced to manage that.
Sky seem to have cropped the picture to 16:9. Terrible quality.
Anyway, why do TV channels continue to broadcast 4:3 games in a 16:9 format? I'm presuming it's because the studio sections are in 16:9?