All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, the statement that the Shafaq (the red twilight) does not disappear until the time of the Fajr prayer appears from the East may not be true, because many Muslims in Britain say that the Shafaq disappears before that but late at night. However, this is a controversial matter between the Muslim community there.
Therefore, the correct opinion in our view is that if trustworthy people confirm that the time of ‘Ishaa’ prayer starts even late at night, then it is not permissible to combine between the two prayers (Maghrib and ‘Ishaa’) as we clarified in Fatwa 99424. However, if it is confirmed that the time of ‘Ishaa’ prayer does not start until when the Fajr starts from the East, then this is not a sound reason for combining the Maghrib and ‘Ishaa’ prayers for many consecutive months. Such combining of the prayers is not legislated in the Sharee’ah (Islamic Law) for the residents. There is nothing in the Sharee’ah that proves that it is permissible to combine between the Maghrib and ‘Ishaa’ prayers for the residents for the entire period of summer. Therefore, you may follow the nearest country to you where the ‘Ishaa’ prayer time is distinguished from the Fajr prayer time, or that after the Maghrib prayer you may estimate a precise time for the beginning of the time of ‘Ishaa’ prayer and then you perform the prayer. This is more correct than the statement that is permissible to combine for several months.
In a narration from the Prophet about the Dajjaal (the anti-Christ), it is stated that he [Dajjaal] would stay on the earth for forty days, one day like a year,... Then the companions asked: “Would one day's prayer suffice for the prayers of the day that is equal to one year?” Thereupon the Prophet replied: “No, but you must make an estimate of time (and then observe the prayer).” [Muslim]
The Prophet did not tell them to combine the prayer in that day that is equal to one year, but he only stated the estimate of the times of the prayer.
Nonetheless, some contemporary scholars issued a Fatwa that it is permissible to combine the prayers for the people who are in the same situation like you. Ibn ‘Uthaymeen was asked about a country where the disappearance of the red twilight – by which the time of ‘Ishaa’ prayer starts – is delayed and it is hard for the people to wait for it, and he said: “If the Shafaq does not disappear until the Fajr begins, or that it disappears at a time that is not enough for performing the ‘Ishaa’ prayer before the staring of the Fajr prayer time, then the ruling that applies to these people is the same that applies to the people who do not have a time for the ‘Ishaa’ prayer, so they should estimate its time according to the nearest country to them where there is a considerable time of ‘Ishaa’, or that they should follow the time of Makkah because Makkah is the Mother of the Towns. However, if the red twilight disappears before the Fajr prayer, in a way that there is a long (enough) time to perform the ‘Ishaa’ prayer, then they are obliged to wait until the twilight disappears unless it is hard for them to wait, then in this case, it is permissible for them to combine the Maghrib and ‘Ishaa’ prayer at the time of Maghrib in order to repel the hardship and difficulty.” (End of quote)
However, even according to the view that it is permissible to combine the prayers in your case, then the view of the majority of the scholars is that when combining the prayers at the time of the first prayer, it is not permissible to leave a gap between the two prayers except a short period of time that is enough for just calling the Iqaamah and performing a quick ablution, however, if a supererogatory prayer is performed between them [the two prayers], then in this case, it is not permissible to combine the prayers, and the second combined prayer [‘Ishaa’] becomes invalid because of performing it before its fixed time while the conditions for the validity of combining the prayers are not met. This is the view that we adopt here in Islamweb.
Finally, we apologize for not mentioning all the views in this regard because this will take a long time.
Allaah Knows best.