Demographics of Iraq
97% of Iraqis follow Islam: 61% Shia and 34% Sunni. 1% of these describe themselves as "Just a Muslim". According to the CIA Factbook, Shias make up 60% of population, while Sunnis 35%. Christianity accounts for 5%, and the rest practice Mandaeism, Yazidism and other religions.
Islam in the United Kingdom
An August 2017 survey by the Bertelsmann Stiftung foundation found that among British Muslims, 75% were Sunni and 8% were Shia.
A September 2017 survey by the Institute for Jewish Policy Research (JPR) found that among British Muslims, 77% were Sunni, 5% were Shia, 1% were Ahmadiyya, and 4% were members of other denominations. 14% of British Muslims said they didn't know or refused to answer the survey.