DOZENS of defectors have deserted Islamic State including two from Britain, shattering the group's self-proclaimed image of a "jihadist utopia", according to a new report.

Since January last year at least 58 individuals have left the group and spoken publicly - and the number is growing, researchers based in London found.

Some fled after they were disappointed by the "quality of life" in territories controlled by IS and realised that the image of luxury goods and cars that lured them to join in the first place had failed to materialise.

The Herald: ICSR logoICSR logo

Defectors were also found to have left after being outraged with the group's brutality and disillusioned by corruption in the ranks.

The study, published by the International Centre for the Study of Radicalisation and Political Violence (ICSR) based at King's College London, said reports of defections have been "sufficiently frequent to shatter IS's image as a united, cohesive and ideologically committed organisation".

One of the defectors is British widow Shukee Begum who was left stranded in Turkey with her five young children after fleeing IS when her husband was killed fighting.

The report reveals that in late August 2014, one disillusioned British fighter for IS contacted a ICSR research fellow, claiming to speak for two dozen of his comrades who had gone to Syria to fight the Assad government.

He said: "We saw the videos. They hyped us up’.

The Herald: Islamic State of Iraq and the Levant (ISIS) logo

But he said the the reality they found was very different. "Muslims are fighting Muslims’, he said: "Assad’s forgotten about. The whole jihad was turned upside down."

The conversation was the first evidence of a ‘disillusioned’ IS fighter.

Researchers tracked 58 individuals - 51 male and seven female - who have turned their back on IS and later spoken out.

The report suggests the pace of public defections has increased, with almost 60% of the cases reported in the first eight months of this year, and nearly a third in the three months to August.

The study said: "They demonstrate that IS is not the jihadist utopia that the group's videos promise; and that many of its own fighters have deep concerns about the group's strategy and tactics."

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In a sign of IS's global recruitment strategy, defectors represented 17 different countries, including two from Britain.

Most felt the group - also known as Isil - had not lived up to their expectations, while four narratives emerging from their stories were singled out in the report.

Scots are among those who are known to have defected.

The Herald: Screengrab taken from a militant video posted on YouTube of Ruhul Amin

Earlier this month it was confirmed that Ruhul Amin, who was born in Bangladesh but grew up in the Froghall area of Aberdeen was killed in a drone strike in the city of Raqqa, Syria.

And Aqsa Mahmood left her family in Glasgow and fled to Syria to join Islamic State in November 2013 and married one of their fighters. She is at the centre of a Metropolitian Police investigation over claims she tried to recruit other young British Muslim women online.

The Herald: Aqsa MahmoodAqsa Mahmood

Among the reasons given from deserting IS was in-fighting, brutality against Muslims, corruption and quality of life.

Defecting from IS is "complex and dangerous", with those who succeed in fleeing the group's territory fearing reprisals or prosecution once they return to their home country, the study said.

It called on governments to do more to remove obstacles that prevent defectors from speaking up, saying their testimony could be help prevent potential new recruits from being radicalised.

The report stressed it "does not attempt to excuse, justify or glorify people's decision to join IS", adding that some are "likely to have committed crimes".