This verdict given by Mufti Muhammad Zubair Butt (damat barkatuhum) deals on the permissibility of performing Jumu’ah prayers in prison. I have read the booklet of Majlisul Ulema of South Africa on the same issue already and that an inmate is not obligated to perform the Jumu’ah prayer in congegration, but instead can perform his Dhur prayer they are agreeing upon. But they seem to differ on the lacking condition of ‘Ithnul Aam’ (public access).
Since Mufti Zubair Butt Sahab seems to be representing the opinion of many classical Deobandi scholars I am posting his conclusion, which has been agreed on by Mufti Taqi Uthmani (damat barkatuhum) as well.
In short, Sheikh Zaadah in Majma’ al-Anhur, al-Haskafi in al-Durr al-Mikhtaar [2:25], al-Sharanbulaali in Maraaqi al-Falaah [p. 510], al-Tahtaawi in Sharh al-Tahtaawi ‘Alaa Maraaqi al-Falaah [p. 510] and his commentary on al-Durr al-Mukhtaar [1:344], and Ibn ‘Aabideen in Radd al-Muhtaar [2:25] and Minhat al-Khaaliq [2:151] have allowed restriction of access for reasons of security. On this basis, it would appear to be permissible to allow the validity of Jumu‘ah Salaah within the confines of a prison even if public access is restricted due to reasons of security. This is also the opinion of Mufti Rashid Ahmad Ludhianvi [Ahsanul Fataawaa, 4:122], Mufti Mahmud Hasan Gangohi [Fataawaa Mahmoodiyyah, 8:183], and Mufti Muhammad Taqi Usmani [Fataawaa Usmani, 1:523].
Therefore, to summarise:
A Muslim prison inmate is not obligated to offer the Jumu‘ah Salaah, but may do so if he wishes [provided all the remaining normal conditions are satisfied]. However, any restrictions on public access must not be with a view to restrict worshipers, but rather must be for genuine reasons of security and administration or due to other legally valid reasons.