British Muslims have led condemnation of the murder of British hostage Alan Henning as a "despicable and offensive act" which showed the Islamic State jihadists who killed him had "no regard for Islam".
Imams and other influential figures had joined forces to appeal to the terrorists to release the aid worker, a former taxi driver from Salford who left his job to travel to Syria to take help to victims of its civil war.
Dr Shuja Shafi, Secretary General of the Muslim Council of Britain, said: "This reported murder is a despicable and offensive act, coming as it does on the eve of the Muslim festival of Eid Al-Adha.
"It is quite clear that the murderers of Alan Henning have no regard for Islam, or for the Muslims around the world who pleaded for his life.
"Alan was a friend of Muslims, and he will be mourned by Muslims.
"In this period of Hajj and this festival of Eid, Muslims remember the mercy of God and the emphasis God places on human life.
"Alan Henning's murderers have clearly gone against that spirit of Islam. Our thoughts and prayers go out to his family."
The UK will use "all the assets we have" to hunt down the Islamic State terrorists responsible for the "senseless" murder David Cameron said this morning.
Speaking after meeting with intelligence and defence chiefs this morning, the Prime Minister said the killing of "a man of great peace, kindness and gentleness" showed that there was "no level of depravity to which they will not sink".
Deputy Prime Minister Nick Clegg said in a statement: "My sincere condolences go to Alan Henning's family.
"The barbaric actions of ISIL are held in complete contempt and we are resolved to defeat this evil.
"Alan Henning was a man moved to selflessly help those most in need and we should remember that above all else at this difficult time."
Labour leader Ed Miliband described the killing as "appalling and barbaric".
Respect Party MP George Galloway described the killing as "a depraved Satanic act committed by devils in human form".
He wrote on Twitter: "It is a desecration of all that is holy."
The ISIS murder of Alan Henning is a depraved Satanic act committed by devils in human form. It is a desecration of all that is holy.— George Galloway (@georgegalloway) October 3, 2014
Tory MP Mark Pritchard said: "If ISIS think the British people will be cowed they are gravely mistaken. For every act of brutality they birth greater national resilience."
And Labour's Fiona Mactaggart - who did not vote in last week's Commons decision to join US-led air strikes against IS positions in Iraq - said the murder made her question her decision.
"The vile murderers of ISIL make me almost wish I voted to bomb in Iraq last week. I want to avenge the death of Alan Hemming. I despise them," she said.
Inspire, an anti-extremist campaign group of British Muslim women, described Mr Henning's death as "an affront to all Muslims across the world".
Co-director Sara Khan expressed her "heartfelt condolences" to the family of the aid worker, who she described as an "amazing man, a man of courage, a man of dignity, a man of integrity".
She said: "The only thing that the killing of Alan has achieved is greater revulsion for ISIS and the fact that more people from across our world, within our communities, Muslims and non-Muslims alike, are united in their stance against their barbarity and inhumanity.
"The murder of Alan Henning is a brutal and criminal act of terror that is an affront to all Muslims across the world."