Isis soldiers: ‘The group has no standing with faithful Muslims.’ Photograph: Alamy

The prime minister and media should stop legitimising the terror group rampaging through Syria and Iraq by describing it as Islamic State, according to a coalition of imams and organisations representing British Muslims. Use of the jihadis’ preferred title, they argue, gives credibility to the Sunni militants and slurs the Islamic faith.

UK Muslims need to do more to dissuade their young men from being misled into taking part in the group’s “hatred and poison”. “We shall take every opportunity to continue to say clearly and loudly ‘not in our name’ and ‘not for our faith,’ ”

We propose that ‘UnIslamic State’ (UIS) could be an accurate and fair alternative name to describe this group and its agenda – and we will begin to call it that.”

Six senior Islamic scholars endorsed the fatwa last month, describing Britons allied to Islamic State (Isis) cells as “heretics” and prohibiting would-be jihadis from joining the “oppressive and tyrannical” group in Iraq and Syria. It is feared that as many as 500 Britons have travelled to Syria or Iraq since 2011 to join the group and its affiliates.

“This could be especially powerful because everybody at home and abroad can see that you are being asked to do so by British Muslims themselves who want to be clear about why this group is so vehemently rejected.

“We are sure that most British Muslims would agree that ‘UnIslamic State’ is a considerably more fitting label for this poisonous group – and hope that our fellow citizens will join us in that.