In the U.K. the original broadcast allocation was 88 to 100MHz with receivers designed accordingly.
The portion from 100 to 104MHz or thereabouts was widely used by police departments around the country, and many people discovered they could listen-in when imported Japanese receivers that went right up to 108MHz became readily available. The police were gradually moved on to other frequencies during the 1980s so that the broadcast band could be extended right up to 108 MHz.
In the U.S. & Canada, the sound carrier for TV channel 6 lies just below the FM band, and it's possible to tune it in on some receivers.
