Swaggering in the desert and glowering menacingly at the camera, this is believed to be notorious Islamic State murderer Jihadi John – filmed unmasked in Syria for the first time.

In a one-minute 17-second video, the knife-wielding fanatic, who has taken part in the gruesome beheadings of at least seven hostages in Syria, including two Britons, vows to continue ‘cutting heads’.

He then promises a triumphant return to Britain with the terror group’s self-styled leader.

Alive: The video, exclusively obtained by The Mail on Sunday, clearly shows a man claiming to be Jihadi John making direct threats to the UK and its citizens. It is the first footage of him since January

The Mail on Sunday has obtained the first footage of the killer to emerge from Syria since he was identified in February as 27-year-old Londoner Mohammed Emwazi.

He was last seen in a sickening IS video at the end of January, beheading Japanese hostage Kenji Goto.

We understand the latest film was shot on a mobile phone about two months ago near the IS-held town of Deir Ezzor in south-east Syria.

In an eight-second excerpt obtained by this newspaper the camera pans away from a flatbed truck upon which a grenade-launcher is mounted, to reveal a hooded Emwazi in profile.

Swathed in black and wearing a cap under his hood, he then turns and stares directly into the lens before looking away to scan the desert.

No sound accompanies the footage we have been given but we have been played an audio excerpt from the full video.

In it, the man thought to be Jihadi John is heard clearly saying, in a British accent: ‘I will carry on cutting heads.’

The film was secretly obtained by rebel fighters of the Free Syrian Army, who sent it to one of their colleagues, known as Abu Rashid, in the Bulgarian capital Sofia.

It was then shown in full to another FSA-linked activist in Istanbul who told us: ‘He looks at the camera and says, “I am Mohammed Emwazi. I will soon go back to Britain with the Khalifa” [the leader of Islamic State].’

The activist continues: ‘He said something more about cutting heads off, “We will kill the kuffar.” Then the camera shows two masked men that looked like bodyguards.’

Chilling: A hooded figure walks into shot, where a grenade-launcher can be seen on flatbed truck (left), before he starts to turn (right). On audio, he refers to himself as Mohammed Emwazi

Terrifying: In the film, he vowed to 'kill the kuffar [unbelievers] and keep cutting heads'

The Mail on Sunday showed the clip to one of the UK’s leading experts on facial mapping, a former policeman who regularly acts as an expert witness in court cases.

After comparing the film to existing images of Emwazi, the expert – who we are not naming for security reasons – said: ‘I have noted a number of apparent similarities in both the morphological and the proportional comparisons and in my opinion the images lend support to the contention that they are the same person.’ This, he added, would be sufficient to result in ‘an arrest being made in most cases and may get a conviction in court’.

Abu Rashid, from the Syrian city of Aleppo, is believed to have received the grainy footage on his smart phone through the video messaging app called Viber. He later passed a copy of the video to Bulgarian counter-terrorist police.

After Emwazi’s true identity was revealed, various pictures of him emerged from his school days in the UK. In one, taken from a Westminster University student card, he is seen wearing a baseball cap.

Last month there was speculation that Emwazi had fled with IS to Libya. Other reports, however, suggested he was on the run inside Syria from his fellow fighters, who supposedly wanted him dead. The new video appears to contradict these reports.

Jihadi John is one of the world’s most wanted men with a £6 million bounty placed on his head by the US. He became the world’s most infamous jihadi after he beheaded American captive James Foley, 40, in the Syrian desert a year ago.

In hiding: Jihadi John has not been seen since he was exposed as 27-year-old Londoner Emwazi in February

It was the first in a series of bloody executions of several Western hostages over the next five months.

After Mr Foley, fellow American Steven Sotloff, 31, was beheaded and Briton David Haines, 44, from Perth, Scotland, became Jihadi John’s third victim. Mr Haines’s death was followed by that of Manchester taxi-driver Alan Henning, 47, whose execution provoked condemnation from the West and the Islamic world as he had travelled to Syria to do humanitarian work with a group of British Muslims.

Identified: A facial recognition expert tells The Mail on Sunday the face in the video shares key features with pictures Emwazi in Kuwait in 2009 and as Jihadi John in Syria

American aid worker Peter Kassig, 26, was Jihadi John’s fifth Western victim and, in January, Japanese hostages Haruna Yukawa, 42, and Mr Goto, 47, became his last two.

Jihadi John has also been seen in a video taking part in the beheadings of at least 17 Syrian soldiers.

British journalist John Cantlie, 45, is the last known Western hostage being held by IS. He featured in IS propaganda videos last year, when he was shown in the northern Iraqi city of Mosul and the war-torn Syrian city of Aleppo.

He wrote an article in May in IS’s monthly magazine called Dabiq, warning how easy it was for the group to acquire nuclear weapons.

In November The Mail on Sunday revealed how official Government sources had confirmed that SAS soldiers had flown to a secret base in the Middle East to prepare for a potential mission to capture or kill Emwazi.

In the same month this newspaper also revealed that Emwazi had been injured in a US-led air strike, according to reports received by the Foreign Office. He was believed to have narrowly escaped death when he attended a summit of the group’s leaders in an Iraqi town close to the Syrian border. And in March we disclosed astonishing emails between Emwazi and a Mail on Sunday reporter in which he spoke of being aware that British security services were closing in on him and that he was a ‘dead man walking’.

His emails were sent before he left Britain to join Islamic State in Syria at a time when Emwazi was claiming to be an innocent victim of MI5 persecution. He warned: ‘I’ll take as many pills as I can so that I will sleep for ever.’

The Mail on Sunday has passed the video we obtained to the Metropolitan Police and security services for further investigation. Scotland Yard declined to comment.

RAF and SAS kill 40 fighters in stunning raid on IS stronghold

The Royal Air Force has launched its most devastating attack against Islamic State to date – killing at least 40 jihadis in a single air strike as missions in Iraq have been stepped up in the wake of the Tunisian beach massacre.

The lethal assault by RAF Tornado jets destroyed an IS fortress near Mount Sinjar, killing more extremists than any previous British mission against the terror group and heralding a major upsurge in the UK’s war effort.

Details of the mission emerged as The Mail on Sunday established that since an Islamic gunman slaughtered 30 British tourists in Tunisia, the RAF has dropped twice as many bombs on IS targets as it did in the same period before the attack.

The increase in strike missions by RAF fighter-bomber aircraft and drones also follows severe criticism that Britain was not doing enough to eradicate the terror group.

Earlier this year, MPs from the Defence Select Committee issued a scathing report of the UK’s response to the threat of IS, describing it as ‘strikingly modest’, with no strategic plan and insufficient military personnel dedicated to the task.

The unprecedented operation was spearheaded by a pair of Tornado GR4 fighter-bombers, an RAF Voyager air-to-air refuelling aircraft and the UK’s new intelligence-gathering Rivet Joint spy plane, which flew over Mount Sinjar and identified an IS command centre, a barracks, ammunition silos and equipment depots.

Then on August 4, the Tornado GR4s took off from RAF Akrotiri in Cyprus, crossed the eastern Mediterranean and flew on a southerly bearing towards Sinjar.

The jets and Rivet Joint then circled overhead while Special Air Service (SAS) and Kurdish Peshmerga troops crept into positions within one-and-a-half miles of the IS stronghold.

The Tornados struck first, launching at least six laser-guided Paveway missiles into the IS positions. Many militants were killed in the blast while others attempted to escape only to meet a barrage of mortars and rocket fire from the SAS and the Peshmerga. The Tornados then refuelled before returning to Cyprus.

Raid: Stills of RAF Tornado GR4s attacking fortified ISIS near Mount Sinjar in Iraq at the beginning of August

A defence source said: ‘Intelligence work allowed the coalition to mount a large, carefully planned air attack on this array of targets, co-ordinated with a barrage of mortar and heavy weapon fire. Initial analysis indicated that the attack was a success.’

Since the Tunisia attack on June 26, the number of sorties by RAF aircraft over Iraq, as reported on a British Government website, has remained relatively constant.

But while approximately 25 missiles were fired in the 50 days before the incident, 50 have been launched since then, according to publicly released figures. Last night, former Chief of the General Staff, Lord Dannatt, said: ‘The Tornado raid on Mount Sinjar is exactly the sort of mission that UK forces should be conducting.

‘Only last year our television screens were filled with the atrocities being committed against the Yazidi and Christian communities in that region.

‘ISIL fighters must understand that there will be a reckoning – sooner or later. Their barbarity will catch up with them.’

A Ministry of Defence spokesperson added: ‘The UK continues to play a leading role in activity that has, so far, seen ISIL lose 25 per cent of its territory in Iraq.