Unfortunately, you won’t be able to watch UFC 252 in the BT Sport. Perhaps you haven’t known this yet; the BT spokesperson confirmed that BT company would end the relationship with the UFC on December 3rd. That means BT Sports will no longer broadcast the UFC events on the channel. The UFC 252 event happens on Saturday, 15 August, 2020. But you can still purchase the PPV through the service.
UFC 252 is the upcoming PPV event. In this case, PPV is the only official way that you can take to watch UFC 252 without any problem. The preliminary fights will be available in UFC Fight Pass, FOX Sports, as well as ESPN. If you have subscribed to either of them, you will be able to watch the preliminary fights for free. However, you will need to purchase the PPV package through UFC.tv to attend the main event of the UFC 252. If you are a subscriber of the UFC.tv, you can watch the UFC 252 main event replay a month after the actual event happens.