Kurdish protesters have been condemned for staging a mock execution outside Downing Street a day after the brutal murder of Alan Henning by the terror group.
The protests, demanding stronger action against ISIS, saw two men wearing blood-spattered orange jumpsuits with knives held to their throats, imitating the ISIS style beheadings.
The stunt has caused outrage amongst Muslim groups who said Mr Henning's death should not be used for political gain.
Expressing his horror at the incident, Mohammed Shafiq, the chief executive of the Ramadan Foundation, said: "I think anyone who has seen the outpouring of grief today will be totally disgusted by anyone who is staging mock executions.
"The Kurdish activists have a right to protest and demand extra weapons, what they do not have the right to do is mock Mr Henning's death and recreate the execution.
"We reject this and condemn it without hesitation. What today should be about is Barbara and Mr Henning's family, not about trying to use the death for political gain."
Several hundred Kurdish activists turned out for the protest, demanding heavy weapons and anti-tank missiles for use against ISIS to deter an attack on the town of Kobani, on the Syria-Turkey border.
The Kurdish community fear that the area is about to be taken over by the terror group, leading to another massacre.
Meanwhile, a second demonstration took place in London as the Stop the War Coalition marched on Downing Street, calling for Britain to halt it's bombing campaign against ISIS in Iraq.
Holding placards that say 'stop bombing Iraq' and 'don't attack Syria', activists described the attacks on Islamic State by the coalition as 'insane'.
One of the protestors Francis O'Neill, 36, from Oxford said that the people of Iraq were being subjected to 'equal barbarity' as that inflicted by ISIS.
He said dropping bombs is not the answer.
"Whether you see someone being beheaded or being hit by a drone strike...It makes no difference."
RAF jets began bombing missions against militant positions in Iraq a week ago and David Cameron announced that two more Tornado bombers will join the mission on Thursday.
Mr Cameron has said he is also considering extending bombardments to Syria, the stronghold of ISIS, where the U.S. and other allies are already attacking.
Alan Henning's wife issued a statement today paying tribute to her husband.
She said: "As a family we are devastated by the news of his death. There are few words to describe how we feel at this moment.
"Myself, Lucy and Adam, and all of Alan's family and friends are numb with grief. Alan was a decent, caring human being. His interest was in the welfare of others.
"He will be remembered for this and we as a family are extremely proud of him and what he achieved and the people he helped."
President Barack Obama condemned the murder of British taxi Driver Alan Henning after a video showing the aid worker being beheaded by an Islamic State militant was released.