Islam is widely considered Europe's fastest growing religion, with immigration and above average birth rates leading to a rapid increase in the Muslim population.
The exact number of Muslims is difficult to establish however, as census figures are often questioned and many countries choose not to compile such information anyway.
Total population: 3.1 million
Muslim population: 2.2 million (70%)
Background: Religious worship was banned in Albania until the transition from Stalinist state to democracy in the 1990s. Islam is now openly recognised as the country's major religion and most Albanians are Sunni Muslim by virtue of the nation's history: The Balkans has had centuries of association with the faith as many parts of it were part of the Turkish Ottoman Empire. While the empire is long gone, the culture remained in place. Significant populations of Albanian Muslims exist in a number of other European countries.
Sources: Total population - Albanian Institute of Statistics, 2005; Muslim population - UK Foreign Office.
Total population: 8.2 million
Muslim population: 339,000 (4.1%)
Background: Large numbers of Muslims lived under Austrian rule when Bosnia-Hercegovina was annexed by Austria-Hungary in 1908. Many of Austria's Muslims have roots in Turkey and others arrived from the Balkans during the 1990s wars - partly because of historical ties. Islam has been recognised as an official religion in Austria for many years, meaning that it has a role in the religious teaching in schools. Vienna has historically been regarded as the point where the Islamic world reached its most western point, a critical battle in Austria in the 16th century marking the beginning of the decline of the Turkish Ottoman Empire.
Sources: Total population - Statistics Austria, 2005 figures; Muslim population - Statistics Austria, 2001 figures.
Total population: 10.3 million
Muslim population: 0.4 million (4%)
Background: Islam is one of seven recognised religions in Belgium, a status that brings it a number of subsidies and official roles, such as providing teachers. Despite this there have been complaints of discrimination. Unemployment and poor housing have been one such cause of tension. There have also been claims of discrimination against women in traditional dress. A majority of Belgium's Muslims are of Moroccan or Turkish origin; many others are from Albania. (Citizenship is available after seven years).
Sources: Total population - Statistics Belgium 2001; Muslim population - US State Department.
Total population: 3.8 million
Muslim population: 1.5 million (40%)
Background: Bosnia-Hercegovina is still recovering from the bloody inter-ethnic war of 1992-95. Around 250,000 people died in the conflict between Bosnian Muslims, Croats and Serbs. Almost 8,000 Muslims were killed by Bosnian Serbs at Srebrenica in 1995 - Europe's worst atrocity since World War II. Many Muslims were displaced, as were members of other communities. A peacekeeping force remains in the country, whose frontiers have long been considered the western borders of the Islamic faith in Europe.
Sources: Total population - Agency for Statistics Bosnia and Herzegovina, 2003 figures; Muslim population - US State Department.
Total population: 5.4 million
Muslim population: 270,000 (5%)
Background: In the 1970s Muslims arrived from Turkey, Pakistan, Morocco and the former Yugoslavia to work. In the 1980s and 90s the majority of Muslim arrivals were refugees and asylum seekers from Iran, Iraq, Somalia and Bosnia. Access to housing and employment have been sources of concern for Muslims in Denmark. (A minority have citizenship).
Sources: Total population - Statistics Denmark, 2004 figures; Muslim population - US State Department.
Total population: 62.3 million
Muslim population: Five to six million (8-9.6%)
Background: The French Muslim population is the largest in western Europe. About 70% have their heritage in former north African colonies of Algeria, Morocco and Tunisia. France favours integration and many Muslims are citizens. Nevertheless, the growth of the community has challenged the French ideal of strict separation of religion and public life. There has been criticism that Muslims face high unemployment and often live in poor suburbs. A ban on religious symbols in public schools provoked a major national row as it was widely regarded as being a ban on the Islamic headscarf. Late 2005 saw widespread and prolonged rioting among mainly immigrant communities across France.
Sources: Total population - National Institute for Statistics and Economic Studies, 2004 figures; Muslim population - French government estimate.
Total population: 82.5 million
Muslim population: 3 million (3.6%)
Background: The majority of the Muslim population is Turkish, with many retaining strong links to Turkey. Others arrived from Bosnia and Kosovo during the Balkan wars. Until recently Muslims were considered "guest workers", who would one day leave the country - a view that is changing. Racist violence is a sensitive issue, with the authorities trying a range of strategies to beat it. Steps are being taken to improve integration.
Sources: Total population - Federal Statistical Office, 2004 figures; Muslim population - Federal Ministry of the Interior estimate.
Total population: 58.4 million
Muslim population: 825,000 (1.4%)
Background: The Muslim population is diverse, the largest group coming from Morocco. Others are from elsewhere in North Africa, south Asia, Albania, and the Middle East. Most arrived from the 1980s onwards, many of them as students. Italy is working to formalise relations between the state and the Muslim community. Up to 160,000 Muslims are Italian born. Most Muslims have the right to reside and work in Italy, but are not citizens.
Sources: Total population - Italian National Statistical Institute; Muslim population - UK Foreign Office.
Total population: 2.1 million
Muslim population: 630,000 (30%)
Background: Macedonia's largest religion is Macedonian Orthodox, but almost one third of the population describe themselves as Muslim. Macedonia was spared the inter-ethnic violence that affected much of the Balkans following the break-up of Yugoslavia. But in early 2001 rebels staged an uprising demanding greater rights for the ethnic Albanian minority - a group which includes most Muslims. With EU and Nato support a deal was reached offering them greater rights, although some have been unhappy with the pace of change. The US State Department suggests that religious freedom is generally respected and that "societal discrimination is more likely to be based upon ethnic bias" than religion.
Sources: Total population - UK Foreign Office; Muslim population - UK Foreign Office.
Total population: 16.3 million
Muslim population: 945,000 or 5.8%
Background: The integration of Muslims remains a concern for the Dutch government, particularly after a film-maker critical of Islam was murdered in 2004 by a radical Islamist. Further tensions surround the view held by some that there is a high level of crime among Muslim youths and a problem with unemployment. In the 1950s Muslims arrived from the former colonies of Suriname and Indonesia. One of the most important groups is the substantial Somali minority. Others are from Turkey and Morocco. The Netherlands favours multiculturalism, essentially the accommodation of different groups on equal terms.
Sources: Total population - Statistics Netherlands, 2005 figures; Muslim population - Statistics Netherlands, 2004 figures.
SERBIA AND MONTENEGRO (WITH KOSOVO)
Total population: 10.8 million (including Kosovo); 8.1 million (excluding Kosovo)
Muslim population: Serbia and Montenegro - 405,000 (5%); Kosovo - about 1.8 million (90%)
Background (excluding Kosovo): Within Serbia and Montenegro the predominant religion is Serbian Orthodoxy. Islam is the second largest faith, with Muslims accounting for about 5% of the population, rising to about 20% in Montenegro. The Muslim community is considered one of seven "traditional" religious communities. Religion and ethnicity remain closely linked across the country and discrimination and tensions continue to be reported.
Kosovo background: The late 1990s saw devastating conflict after the Kosovo Liberation Army, supported by the majority ethnic Albanians - most of whom are Muslim - came out in open rebellion against Serbian rule. Yugoslav President Slobodan Milosevic began "ethnic cleansing" against the Kosovo Albanian population. Thousands died and hundreds of thousands fled. Nato intervened between March and June 1999 with a 78 day bombing campaign to push back Serb forces and Kosovo remains under UN control. The ethnic Albanian community has expressed frustration at the length of time being taken to decide Kosovo's future status. Attacks against Kosovo's remaining minority Serb population have caused concern.
Sources: Total population - UK Foreign Office; Muslim population - US State Department.
Total population: 43.1 million
Muslim population: 1 million (2.3%)
Background: Almost eight centuries of Moorish rule over Spain came to an end in 1492, providing the country with a strong Islamic legacy, particularly in its architecture. The modern Muslim population started to arrive in significant numbers in the 1970s. Many were Moroccans coming to work in tourism and subsequent growth came when their families joined them. The state recognises Islam, affording it a number of privileges including the teaching of Islam in schools and religious holidays. There have been some reports of tension towards Muslim immigrants. Spain was shaken in 2004 when terror attacks by suspected radical Islamists killed 191 people on Madrid commuter trains.
Sources: Total population - Spanish National Institute of Statistics, 2005 figures; Muslim population - US State Department.
Total population: 9 million
Muslim population: 300,000 (3%)
Background: The Muslim population is broad - with significant groups from Turkey, Bosnia, Iraq, Iran, Lebanon and Syria. The size of the Muslim population is such that representative bodies receive state funding. Sweden favours multiculturalism and immigrants can become citizens after five years. Sweden prides itself on its tolerance, but there has been criticism that Muslims are too often blamed for society's problems.
Sources: Total population - Statistics Sweden, 2005 figures; Muslim population - US State Department.
Total population: 7.4 million
Muslim population: 310,800 (4.2%)
Background: Official figures suggest the Muslim population has doubled in recent years, but some sources say there are also about 150,000 Muslims in the country illegally. The first Muslims arrived as workers in the 1960s, mostly from Turkey, the former Yugoslavia and Albania. They were joined by their families in the 1970s and, in recent years, by asylum seekers. (Comparatively few have citizenship.)
Sources: Total population - Swiss Federal Statistical Office, 2003 figures; Muslim population - Swiss Federal Statistical Office, 2000 figures.
Total population: 68.7 million
Muslim population: 68 million (99%)
Background: Although Turkey is a secular state, Islam is an important part of Turkish life. Its application to join the EU divided existing members, some of which questioned whether a poor, Muslim country could fit in. Turkey accused its EU opponents of favouring a "Christian club". Membership talks were formally launched in October 2005, with negotiations expected to take 10 years. Most Turks are Sunni Muslim, but a significant number are of the Alevi branch of Shias.
Sources: Total population - Turkish State Institute of Statistics, 2003 figures; Muslim population - US State Department.
Total population: 58.8 million
Muslim population: 1.6 million (2.8%)
Background: The UK has a long history of contact with Muslims, with links forged from the Middle Ages onwards. In the 19th Century Yemeni men came to work on ships, forming one of the country's first Muslim communities. In the 1960s, significant numbers of Muslims arrived as people in the former colonies took up offers of work. Some of the first were East African Asians, while many came from south Asia. Permanent communities formed and at least 50% of the current population was born in the UK. Significant communities with links to Turkey, Iran, Iraq, Afghanistan, Somalia and the Balkans also exist. The 2001 Census showed one third of the Muslim population was under 16 - the highest proportion for any group. It also highlighted high levels of unemployment, low levels of qualifications and low home ownership. The UK favours multiculturalism, an idea shared by other countries which, in general terms, accepts all cultures as having equal value and has influence over how government engages with minorities.
Sources: Total population - Office for National Statistics, 2001 figures; Muslim population - Office for National Statistics, 2001 figures.
BBC - Islam in Europe