To watch BT Sport via satellite, you need an active Sky viewing card that the subscription can be added to. That doesn't mean that you actually have to pay Sky for TV any more, but you have to have the card, and a box that accepts it.
Thanks Ectophile. Does this mean I have to retain my SKY + box (to take the new viewing card you suggest), the Freesat box which I am about to buy, and my YouView box that was supplied to me by BT?. Can I use the existing viewing card that I currently have in the SKY+ box.
When you cancel Sky your current card becomes a Freesat from Sky card which you can still use to receive BT Sport. To use the card you will need a box that it fits in. The easiest way is for you to retain your Sky box, although you will not be able to record with it.
The Humax freesat boxes (I have the older Foxsat HD and Foxsat HDR) do not have a slot for the Sky card.