Thanks Jeff, good shout that! I forgot about all Europa League games being on BT... Guess I will need it for that then. Is the month pass from when you buy it, or to the calendar month?
The standalone month pass direct from BT lasts 30 days from the day you buy it. It's not cheap at £25 a month though. https://www.bt.com/sport/monthly-pass
If you have a broadband or mobile contract with BT, EE, plusnet etc there are cheaper options.