A British research institute has received £25 million in cash from the Bahraini government since 2011, leaked documents published in the Guardian show.

According to the report, the International Institute for Strategic Studies (IISS), a global think tank specialising in researching political conflicts and armed movements, has secretly accepted £25 million in donations from the Manama government.

The documents also suggest that the Bahraini royal family has agreed to keep the majority of the donations secret. It is thought that the Manama government donated the large sum as a political lobbying mechanism. It is alleged that the secret Bahraini donations account for over a quarter of IISS’ income. Since the report has been leaked, many questions about the research credibility of IISS have been raised. Many have accused IISS of undermining its political independence and expressed their mistrust of the institute.

IISS has dismissed the reports as fabricated.

Bahrain is notorious for its crackdown on freedom of speech and other rights, after what was suspected to be an Iran-backed revolt of primarily Shia Bahrainis was crushed in 2011.

Since then, journalists, academics and citizens who speak out against the government have been systematically arrested and allegedly tortured while in prison for their dissent.