The emir of Qatar will visit Britain this week amid accusations his country has financed extremist Islamist groups in Syria. Qatari officials deny any links with extremist groups and say they are working with the West to support moderate opposition groups in Syria.
On the battlefields of Syria and Iraq, ISIS or Islamic State boasts modern weaponry. The group claims financial assets of tens of millions of dollars.
Analysts say part of that wealth was looted in Iraq and Syria. But some Gulf States are charged with providing support for Islamist groups. Qatar has been accused of links with al-Qaida offshoot the al-Nusra Front, says Jane Kinninmont of policy institute Chatham House.
“Quite a lot is speculation; by the nature of these activities there is not a great deal in the public domain. But there are clearly very serious worries about private financing from Qatar, but also from Kuwait and Saudi Arabia," said Kinninmont.
Speaking during a trip to Berlin last month, the Emir of Qatar, Sheikh Bin Hamad Al-Thani, strongly denied any links with extremist groups.
"Qatar will certainly not support terrorist or extremist organizations, be it in Syria or Iraq," said Hamad Al-Thani.
On the eve of Sheikh Bin Hamad Al-Thani’s visit to London, Islamic State released a video on the Internet, purportedly showing British hostage John Cantlie forced to adopt the role of a mock television reporter in the besieged border town of Kobani.
The emergence, and brutality, of Islamic State has forced Qatar and other Gulf states to backtrack, says Michael Stephens, head of the Royal United Services Institute in Qatar.
“I think there is a certain amount of introspection going on in the Gulf to do with what groups they were funding and how they produced the funding which then led to the creation of ISIS," said Stephens.
It is likely that moderate fighters once supported by Qatar and other Sunni states have been radicalized over that period, says Jane Kinninmont.
“Once people, money and arms go into a complex civil war that is going on over several years, some of those people may not end up exactly where you thought they were in the first place," she said.
Speaking in Egypt last week, U.S. Treasury Secretary Jacob Lew pledged to take on the financial networks supporting extremist groups like ISIS.
“We are, in the United States, determined to work with all of our allies in the region, not just on a military basis, but on a financial basis to make sure that the resources do not continue to flow in," said Lew.
Several Gulf States, including Qatar, have joined the U.S.-led airstrikes on ISIS. Again, Michael Stephens:
“There has been, by the activity of this coalition, a sort of taking back of all these aggressive words which have been going between the West and the Middle East, about who was funding who," he said.
The emir will meet the queen and hold talks with Prime Minister David Cameron. Qatar has invested billions of dollars in Britain and analysts say economic ties will be high on the agenda.