Al-Qaeda appealed to Isis to release the British hostage Alan Henning because it believed he was an innocent aid worker who was genuinely trying to help suffering Muslims, it can be revealed.

In evidence that the depravity exhibited by Isis is now repelling Muslims of all views and backgrounds, even the terrorist group behind the 11 September attacks on the US in 2001 decided that kidnapping the aid-convoy volunteer was a step too far.

Mr Henning, a taxi driver from Eccles, Salford, was so moved by the plight of Muslims in Syria that he decided to miss last Christmas with his wife and two children and travel 4,000 miles to deliver medical equipment to refugees holed up in the town of Al-Dana. A local commander – or emir – of Jabhat al-Nusra, the al-Qaeda affiliate in Syria, visited his then-allies in Isis four days after Mr Henning, 47, was captured. The emir confronted the kidnappers, arguing that their actions were “wrong under Islamic law” and “counter-productive”, according to a journalist who interviewed the man immediately after the encounter.

The world has looked on in disbelief in recent weeks as fighters from Isis, also known as Islamic State, have beheaded three Western journalists and aid workers, including a Briton, David Haines. In a video posted online on Saturday night, Isis warned that Mr Henning would be next.

oday, the Foreign Secretary, Philip Hammond, admitted that special forces were struggling to mount a rescue mission because intelligence chiefs did not know exactly where Mr Henning was being held.

Bilal Abdul Kareem, a US film-maker who has reported extensively from Syria, told The Independent that “anybody of any influence” – including al-Qaeda – had appealed to the Sunni militant group when it seized Mr Henning in December, warning that such a move would backfire. He said: “Four days after he was captured, the emir went to Al-Dana and said: ‘Look, what you are doing is wrong. You have no business what you are doing. You have no right to abduct him. You have no reason to detain him just because he is not Muslim’.”

Mr Henning was the only non-Muslim in a group of volunteers from a UK-based Islamic charity, which organised a convoy of old ambulances to transport medical supplies to Al-Dana, a few miles from the Turkish border. He was abducted on Boxing Day last year.

Mr Kareem said: “I spoke to the emir from Jabhat al-Nusra after he came back. Initially, he was confident that Henning would be released because that is what Isis was saying. But then Henning was removed from his prison in Al-Dana and never heard of again.”

News of Al-Qaeda’s attempt to save Mr Henning echoes reports that the terror group once led by Osama bin Laden passionately disagrees with the direction taken by Isis, which has quickly taken control of an area the size of Great Britain inside Syria and Iraq.

Professor Peter Neumann, the director of the International Centre for the Study of Radicalisation, based at King’s College London, said: “Al-Qaeda has been critical of Isis in recent months. It understands how its behaviour will be perceived by the Western public. Although the two groups’ underlying ideology is still very similar, Al-Qaeda is much more strategic. For example, it is not opposed to beheadings but realises it makes no sense to carry them out in the way that Isis does because this tactic will lose them a lot of friends.”

Dr Afzal Ashraf, a consultant at the Royal United Services Institute, who holds a doctorate in terrorist ideology, said: “The murders of these innocent Western hostages, and the latest threats made against Alan Henning, just go to show how completely incomprehensible Isis’s strategy is. It is absurd and Al-Qaeda realises such behaviour will turn potential recruits away.”

On his internet blog, Mr Kareem provided more details of the discord among Islamist extremists over the abduction of Mr Henning. “Isis said that he was suspected to be a spy,” he wrote. “The Muslims on the convoy asked for proof as they regarded this as a totally ridiculous claim. Isis cited that they could not believe that a white Christian would want to come to Syria at this time, except that he was a spy.

“The Isis commander then showed them Henning’s passport and said that this was the proof, [saying]: ‘There is a secret chip inside. This is so that the intelligence service can continue tracking him.’ One of the other Muslims from the convoy said: ‘All of the passports from the UK are like that!’, showing him his UK passport.

“The other Muslims on the convoy told them that this man had given up Christmas with his family to come to help save the people that Isis said it was trying to save.”

Later, Mr Kareem claimed that Isis was confronted by rival groups, which implored it to release Mr Henning. “Isis said that he was to remain their prisoner and they would ransom him for something. ‘Why?’ they were asked. They said: ‘We will trade him for someone in the UK prison system.’ The other Muslims told him this was not Islamically correct and they had no charge against him.

“One of the aid workers told them that the people rely on these convoys and actions like these would create problems for their efforts in helping the Syrian people. The Isis commander replied: ‘We don’t need convoys – we have Allah’.”

Meanwhile, Mr Haines’s teenage daughter, Bethany, posted a message on Facebook, saying she had been “touched” by the support she had received from the public following his murder.

She wrote: “Hi, I’m David’s daughter who lives in Perth. I was really touched by the messages of support during this hard time. I know my dad would be really touched and grateful.”

Belfast Telegraph