What is the right answer
    concerning the start of Fajr in Northern England?
Question

                I wish to ask you about the problem of
    praying ‘Isha and Fajr in the region of Newcastle in Britain. The Muslims here in
    Newcastle have a big problem with defining the right time for Fajr and ‘Isha’
    prayers, and the time for starting the fast, because the light reaches the surface of the
    earth before the sun rises, and stays there after it has set, for a long time, and
    sometimes this light remains there for the entire night. The astronomers here have divided
    this period when the light appears until the sun rises, and when remains after sunset
    until it disappears, into three:when the intensity of the light is such that a person is able to do some
        work
when the light is such that a person cannot do any work that needs light
total darkness.
The question here is: how do we define the beginning of the time for
        Fajr and ‘Isha’ and for starting to fast in the light of the times given by
        these astronomers’ calculations?
Praise be to Allah.In defining the times of prayer, the astronomers’ calculations do
    not matter. For determining the time of Fajr, what counts is the appearance of a
    horizontal line of light on the eastern horizon. The time for Fajr starts when this line
    becomes clear and distinct, and it ends when the sun rises. The time for Maghrib starts
    when the disk of the sun has set, and it doesn’t matter if there is still light after
    the disk of the sun has disappeared. The time for ‘Isha’ begins when the red
    afterglow of sunset disappears.
The time for fasting begins when the time for Fajr begins, as we have
    explained above, and the fast ends when the disk of the sun itself has set, even if some
    of its light remains afterwards.