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BA is rolling out a Wi-Fi service which allows streaming (for a fee): https://www.britishairways.com/en-fr/information/entertainment/wifi-on-board
However: - their goal is to have 90% of their aircraft connected by 2019. Until then, you can't know for sure if Wi-Fi is available on the specific aircraft or flight. Also, as usual, focus is on long-haul aircraft first.
contrary to what some US airlines do, they don't seem to advertise in advance which flights will or will not have Wi-Fi
you can only use it above 10 000 feet, which for a Glasgow-London flight is going to be a quite short period of time, especially once you take out the time to actually connect to the service, pay for it, etc.
they aim to deliver 1 Mbps on the "Stream" package, which is quite low and will probably deliver a low-quality experience
pricing for the "Stream" package