A filmmaker, who was involved in the early negotiations to free Alan Henning, has told Sky News how even al Qaeda thought holding him hostage was "not a good idea".
The terrorist group sent a member to bargain with the Islamic State fighters holding him but failed to secure his release.
The al Qaeda member, who was sent to bargain with the Manchester taxi driver's captors, said the jihadists were "difficult" and "tough".
Bilal Abdul Kareem told how Mr Henning, who was helping to make an aid delivery in Syria, was captured just an hour after arriving in al-Dana, around 30 minutes from the Turkish border, on Boxing Day.
He said Islamic State fighters had arrived in the town and detained all of those in the convoy but quickly released the Muslim members, holding only Mr Henning.
Mr Kareem said when Mr Henning was first taken he was set to be released later that day or even the next but when that did not happen people started to worry.
Then the jihadists claimed the 47-year-old, father-of-two as their prisoner and said they were planning to exchange him for people in British custody.
Mr Kareem said: "They had a course of action that they were going to take and nobody was going to be able to talk them out of it.
"Even al Qaeda affiliates al Nusra went there to talk to them because nobody outside of ISIS thought this was a good idea, nobody thought that it was OK to do this, none of the other groups were doing that, nobody thought it was a good idea.
"When the al Qaeda representative went to go down and try to talk to them he returned, his face was different, he said something to the effect these guys are really being difficult, really being tough but they did say that they were going to release him.
"Everybody was anticipating that but that never happened."
On Friday the terrorists posted a video of Mr Henning's killing. In it he is pictured kneeling in front of a masked man, who speaks with a British accent and is believed to be the man responsible for previous beheadings.
The man makes a direct appeal to David Cameron saying: "The blood of David Haines was on your hands, Cameron. Alan Henning will also be slaughtered, but his blood is on the hands of the British Parliament."
Muslim leaders have condemned the beheading on the eve of the Muslim festival of Eid Al-Adha, which represents a day of mercy, and said they want to see justice done.
As the community of Eccles mourned, Mr Cameron said Britain would use all of its assets to destroy Islamic State.
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Gallery: Profile: Alan Henning
Alan Henning, 47, was born in Salford, Greater Manchester. Friends gave him the nickname "gadget" due to his love of technology
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He was married for 23 years and he had a teenage son and daughter
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He worked as a self-employed taxi driver
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Mr Henning saw the plight of Syrian people and volunteered with a Muslim charity. He had been to the region at least three times
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He drove life-saving medical equipment from the UK to Syria in old ambulances. He left in December 2013 to make the 4,000-mile trip
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He was kidnapped by IS in Syria by masked men. He may have been held in Ad Dana near Aleppo, then Raqqa