Isis video claims to show beheading of British hostage David Haines

Militants with the Islamic State jihadi group have released a video that appears to show the beheading of a British hostage, David Haines, an aid worker who was captured just days after he arrived in Syria last year.

British government officials were seeking to authenticate the video which purported to show the final moments of Haines, who was 44.

In the video, entitled A Message to the Allies of America, a masked man is shown carrying out the beheading of Haines, whose life had earlier been threatened in a film showing the murder of American journalist Steven Sotloff. The video, which runs to two minutes and 28 seconds, ends with a warning that a second British hostage would be the next to die. He has been named in international media and on social media as Alan Henning, a British aid worker.

The aid worker was taken while working for Acted in Syria in March 2013

Haines is the third western hostage and the first Briton to be killed in this fashion by Isis – the first, US journalist James Foley was murdered in a video released on 19 August.

The British prime minister, David Cameron, issued a statement denouncing the killing. “This is a despicable and appalling murder of an innocent aid worker. It is an act of pure evil. My heart goes out to the family of David Haines who have shown extraordinary courage and fortitude throughout this ordeal.

“We will do everything in our power to hunt down these murderers and ensure they face justice, however long it takes.”

Cameron will gather senior representatives of the military and security services and the Foreign Office and Home Office in Whitehall to discuss the situation.

The US president, Barack Obama, also condemned the killing. “The United States strongly condemns the barbaric murder of UK citizen David Haines by the terrorist group Isil,” he said, using his administration’s preferred acronym for Isis. “Our hearts go out to the family of Mr Haines and to the people of the United Kingdom.

“The United States stands shoulder to shoulder tonight with our close friend and ally in grief and resolve. We will work with the UK and a broad coalition of nations from the region and around the world to bring the perpetrators of this outrageous act to justice, and to degrade and destroy this threat to the people of our countries, the region and the world.”

The recording features a voiceover delivered by an Isis militant, whose voice and accent closely resembles that of the killer in both the Sotloff and Foley videos. The killer directly addresses Cameron, saying that Haines “has to pay the price for your promise” to arm Kurdish peshmerga fighters against Isis.

A still from a video purportedly showing British hostage David Haines kneeling next to an Islamic State fighter. Photograph: ISLAMIC STATE VIDEO/EPA

Speaking to the camera, the hostage, composed but clearly under duress, and wearing an orange jumpsuit, reads out a statement in which he says that Cameron is “entirely responsible for my execution” for entering into a coalition with the US.

Haines, who was in the Royal Air Force for 12 years before moving into aid work, addresses Cameron, saying: “You entered voluntarily into a coalition with the United States against the Islamic State, just as your predecessor, Tony Blair, did, following a trend amongst our British prime ministers who can’t find the courage to say no to the Americans.

“Unfortunately, it is we, the British public, that will in the end pay the price for our parliament’s selfish decisions.”

The killer, swathed in black, then makes a statement in which he makes a direct reference to the British government’s aid to Kurdish fighters.

He says: “This British man has to pay the price for your promise, Cameron, to arm the peshmerga against the Islamic State. Ironically, he has spent a decade of his life serving under the same Royal Air Force that is responsible for delivering those arms.

“Your evil alliance with America which continues to strike the Muslims of Iraq and most recently bombed the Haditha dam will only accelerate your destruction. And playing the role of the obedient lapdog, Cameron, will only drag you and your people into another bloody and unwinnable war.”

At the end of the latest video, another hostage, Henning, is paraded.

The US carried out at least nine air strikes last week on Isis militants threatening the Haditha dam. The bombing was cited by Haines’s killer in the video.

A spokeswoman for the Foreign Office in London said: “We are aware of the video and are working urgently to verify the contents.”

Isis had threatened to kill Haines, a father of two, in a video that emerged 11 days ago in which Sotloff was murdered. Less than 24 hours before the latest video emerged, the Haines family had made a plea to the jihadis to respond to their efforts to make contact.

The family statement, which was released by the Foreign Office and addressed the militants directly, said: “We are the family of David Haines. We have sent messages to you to which we have not received a reply. We are asking those holding David to make contact with us.”

Haines was born in East Yorkshire but raised in Perthshire, and before his capture was living in Croatia with his second wife Dragana.

He had a 17-year-old daughter with his first wife Louise, and a four-year-old daughter with Dragana, who has described him as a “fantastic man and father”. He was kidnapped while working for the aid organisation Acted, having previously worked in Libya and South Sudan.

A meeting of the British government’s emergency committee, Cobra, is expected to be called imminently and the prime minister’s attentions will be diverted from the referendum on Scottish independence, due to take place on Thursday.

Haines had worked for aid agencies in some of the world’s worst trouble spots, including Libya and South Sudan.

He was in Libya during its civil war in 2011, working as head of mission for Handicap International, which helps disabled people in poverty and conflict zones around the world.

by Daniel Boffey and Raya Jalabi

The Guardian