The Islamic State may have up to 42 million supporters across the Arab World alone, according to research conducted by the Clarion Project think tank.

The organisation, which boasts Muslim anti-extremism activists as its board members, calculated the figure by looking at opinion polls from the region, and calculating the amount of positivity felt towards ISIS by its inhabitants.

The Clarion Project wrote:

The estimate is based on a March 2015 poll by the Iraq-based Independent Institute for Administration and Civil Society Studies;  a November 2014 poll by Zogby Research Services; another  November 2014 poll by the Doha-based Arab Center for Research and Policy Studies and an October 2014 poll by the Fikra Forum commissioned by the Washington Institute for Near East Policy.

In Iraq, around 4 per cent are said to view ISIS positively “to some extent”. This means the terrorist group has “between 651,720 and 1,955,160 supporters in Iraq.”

The number rises dramatically in Syria, though it is not known to what extent interviewees are coerced into answering positively, or if they do so out of fear of ISIS reprisal.

“Seventeen percent of Syrians said that they completely support the Islamic State’s goals and activities in the March 2015 poll. That statistic grows to 27% when you account for Syrians who do not consider the Islamic State to be a terrorist group.

“The November 2014 poll interviewed 900 Syrian refugees in Lebanon, Jordan and Turkey and found that 4% are positive towards the Islamic State and another 9% are somewhat positive. This should raise serious concerns for countries that are accepting refugees from the civil war.

“With a population of 17,952,000, that means the Islamic State has between 3,051,840 and 4,847,040 supporters in Syria.”

Figures from other Islamic or Arab countries – including the Palestinian territories (20 percent), Tunisia (13 percent), Egypt (3 percent), Saudi Arabia (10 percent), the United Arab Emirates (13 percent), Yemen (up to 7 percent), Jordan (up to 14 percent), Libya (up to 7 percent), and Lebanon (1 percent) – reveal that in total, ISIS could have between 8.5 million and 42 million supporters, sympathisers, or those that consider it a legitimate political force in the Middle East and North Africa.

“With a minimum of 8.5 million strong supporters and 24.5 million who view the group at least somewhat positively, the Islamic State has plenty of room for growth in the Arab world,” wrote Ryan Mauro, the head of national security for the Clarion Project.