Spies are close to identifying the hooded jihadist dubbed Jailer John who beheaded the journalist James Foley, Britain's ambassador to the U.S. revealed today.

'I can't say more than this but I know from my colleagues at home that we are close,' Peter Westmacott told CNN. 'We're putting a lot into it and there are sophisticated technologies, voice identification and so on which people can use to check who these people are'.

A ‘significant force’ of SAS soldiers and signallers have deployed to northern Iraq in the hunt for the extremists, who spoke with British accents and callously boasted of making personal fortunes from ransoms paid for other released hostages.

The gang openly talked of making so much money they could ‘retire to Kuwait or Qatar’, according to testimonies by former hostages obtained by The Mail on Sunday.

The revelation comes as CCTV footage emerged reportedly showing the moment five separate British jihadis strolled through the departure lounge of Gatwick Airport on their way to fight in Syria.

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Chilling: CCTV footage has emerged which reportedly shows five British jihadis walking through Gatwick Airport on their way to Syria. Second left is Mashadur Choudhury, far right is Muhammad Hamidur Rahman

Different fates: Mashadur Choudhury, 31 (left) returned weeks later and became the first Briton to be convicted over the current conflict in Syria. Former Primark worker Muhammad Rahman (right) was killed while fighting

They are all among more than 500 Britons who have enlisted with jihadist groups in Syria and Iraq, prompting warnings of new terror laws from the Home Secretary.

The Gatwick video, which emerged today, purports to show a group of five British jihadis from Portsmouth leaving the airport for Turkey early on October 8 last year.

According to the Sunday Telegraph, the men booked a return journey but instead used an intermediary to cross the border into Syria where they joined militants.

One of the men is said to be 31-year-old Mashadur Choudhury, who returned just weeks later and in May became the first Briton to be convicted of a terror offence in relation to the current conflict.

His 12-day trial at Kingston Crown Court saw social media evidence of him talking about dying a martyr's death and setting up a group called the al-Britani Brigade Bangladeshi Bad Boys.

The trial also heard how he went on a spending spree with £35,000 which he had borrowed from his family, including a £17,000 Audi A6 and £200 prostitutes.

A different kind of holiday: The group of men walking down a corridor of Gatwick Airport as they left for Turkey

Toll: At least one of the men who is reportedly pictured in the footage has since been killed, said his father

Another of the men was reportedly fellow Portsmouth resident Muhammad Hamidur Rahman.

The 25-year-old was sacked from his job as a Primark store supervisor a month before he left for Syria last October.

His time as an Islamist fighter was short-lived, as his father said earlier this month that he had been killed during the conflict.

The ease with which the men left the country comes despite promises of new laws to crack down on British extremists by the Home Secretary Theresa May. Yesterday she insisted authorities had already excluded more than 150 people from Britain.

But she was also widely mocked by Labour, a Muslim MP and outspoken Tory David Davis over proposed new laws to stop radical preachers when they were likened to 'Asbos for terrorists'.

A Mail on Sunday investigation, meanwhile, reveals more startling information about the four Islamic State militants who were nicknamed The Beatles by their Western captives.

Is this Jihadi John? UK police have photographs of several suspects they believe are now working for ISIS. Pictured is rapper Abdel Majed Abdel Bary, 23, from London

Junaid Hussain, who has a Birmingham accent, is another UK suspect featured on a Jihadi website, believed to be linked to the ISIS terrorist organisation. He posts on Twitter under the name Abu Hussain al-Britani

The men were reported to be ‘interested in money’ from the start of the kidnap ordeal, even bragging to prisoners about how much they were making.

A security source revealed last night that £24 million was paid by at least four European countries for the release of 11 hostages last year.

British and US hostages were seen as being in a ‘different category,’ he said – so demands for an £80 million ransom on Foley were set deliberately high as a provocation.

It has also emerged that:

• Security services believe they are close to identifying the British militants who executed Foley.

• The East Londoners formed a specialist kidnap gang, operating in Syria for up to two years.

• They are thought to have possibly been involved in the seizure of several Westerners, including Foley.

• Their leader was not ‘John’, the left-handed man wielding the knife in the horrific video of Foley’s death, but ‘George’, who goes under the nom-de-guerre of Abu Muhareb (‘Fighter’).

• One former hostage described them as ‘sadistic psychopaths’, regularly handing out brutal ‘punishments’ that included the use of Tasers on hands and bodies.

• They were so vicious that at one stage they were stopped from guarding hostages by IS.

• IS claims it has ‘sleepers’ already in position in the UK and US, ready to strike at any time.

This man is believed to have travelled to Syria from Portsmouth and has similar eyes to Jihadi John

The sickening beheading of Foley, shown off in a slick and distressing propaganda video, highlighted the shameful role being played by British members of Islamic State.

Security services in Britain and the US have drawn up a shortlist of suspects. They believe there may have been more than one killer, since two different knives feature in the footage, but have not yet definitively identified those behind the murder.

DID FOLEY'S KILLER APPEAR IN ANOTHER MURDER VIDEO IN MAY? Security agencies hunting James Foley's killer are analysing another murder video from earlier this year. The footage was posted on the social networking site Instagram in May and features the execution of a solder who was captured by extremists in Syria. According to the Sunday Telegraph, officials believe there are clues that a Briton who features in the video could be the same person who beheaded the U.S. journalist. A security source told the newspaper: 'We can't afford to rule anything out'. Although the killers' faces are covered and the background is a nondescript desert, the mannerisms and stance of the men are expected to be closely analysed. But there are many doubts - as the men could have held knives in their left hand as a red herring to investigators, or their British accents could have been over-dubbed. Advertisement

The Mail on Sunday has pieced together an unprecedented picture of the British gang’s brutal operation and its savage treatment of seized captives through extensive interviews with hostages, family and security sources.

The detailed investigation also uncovered disturbing details of how the world’s wealthiest terror group is being funded by ransom payments, with £8 million paid for the release of four French hostages alone.

Two years ago, the United States said such payments had become ‘the most significant source of terrorist funding’. Britain and the US refuse to pay ransoms. The disclosure that British militants talked among themselves and with their captives about ‘retiring’ with the money they were making demolishes any idea they are motivated purely by religious fervour.

Our investigation revealed the existence of four Beatles – not three as has been widely reported – nicknamed John, Paul, George and Ringo by their Western captives.

The gang’s ringleader was ‘George’, who spent much of his time regurgitating chunks from the Koran and promoting IS’s extremist brand of Islam at public events.

The hostages concluded he was not very smart – unlike ‘John’, who used the nom-de-guerre ‘Abu Saleh’ (‘Pious’) and was seen wielding the knife in the video of Foley’s murder.

‘Ringo’ was also frequently seen, unlike ‘Paul’ who appeared in their cells the least. ‘He seems to have been just a guard, not there all the time,’ said one key figure.

They were also guarded by French-speaking jihadis – at least one of whom was Belgian. According to these accounts, the British gang spoke among themselves in English, struggling with Arabic when asked to translate statements for victims to read on video.

This led captives to conclude their tormentors were second-generations Britons; they debated whether the extremists were from Pakistani or Somali backgrounds.

Hunted: Rapper Abdel-Majed Abdel Bary, from west London, is one of those who is being investigated

One of the jihadis, who posts on Twitter under the name Abu Hussain al-Britani, has been widely reported for several months as being 20-year-old computer hacker Junaid Hussain.

He was just 18 when he was jailed for six months in 2012 for posting sensitive details online about former Prime Minister Tony Blair.

Some, but not all, of the Westerners were tortured – with the thuggish British fanatics feared more than other militants for their viciousness. ‘They did the worst stuff in the world,’ said one family source. This violence included beatings and the use of Tasers to give electric shocks.

Hostages said the British militants were removed at one stage for excessive brutality against them.

They said the gang seemed to flit between carrying out kidnap operations on Westerners, fighting on the front line and guarding hostages.

One well-placed source revealed their cars were identified from number plates as being used in ‘multiple’ kidnaps. ‘This appears to be a professional kidnap team,’ he said. ‘There is a good likelihood that some were involved in the kidnapping of many of the Westerners, including Foley.’

The American freelance journalist was seized in November 2012, when kidnappings were starting to take off in Syria.

In the early days of the uprising, journalists were valued for giving voice to rebels seeking democracy.

Targets: Some of the militants believed to be with IS who are being hunted by the security services

Reporters and aid workers began being grabbed from the streets by criminal gangs. Most ended in the hands of rebel militia, especially the increasingly-influential jihadist groups who saw them as valuable financial and propaganda tools.

There are at least seven Western hostages – three of them American – currently controlled by IS in North-Eastern Syria. Others are being held by a motley variety of rebel militia and criminal gangs, sometimes claiming to be IS to ramp up ransom payments.

Seized Westerners said they were frequently moved, often every few weeks, and held together in gloomy basements and cellars. The French hostages confirmed to security sources after their release that they had shared cells.

The hostages were divided over whether The Beatles themselves carried out ransom negotiations, fixed the prices on their heads or wrote chilling emails sent to their families.

Foley, however, was treated differently from the start. He was barred from contact with his family and there was no ransom demand for the first year of his captivity – then when one was sent, it was set preposterously high at £80 million.

American hostages – especially Foley, whose brother was discovered to be serving in the US Air Force – were picked out for the most brutal beatings.

Respected: Foley (pictured) was a freelance contributor to GlobalPost and was kidnapped while in Syria

‘From the beginning, they were interested in hitting America,’ one hostage told a friend. ‘The more they can do to point the arrow into America, they more they will do. They think America is evil.’

Nicholas Henin, a French journalist, has described how his fellow captive Foley ‘became the jailers’ punch bag’ yet remained impassive, despite terrible abuse.

Western hostages endure mock executions, are routinely accused of being spies, and are forced to suffer terrifying interrogations.

One European photographer was told he must be a spy since his country had friendly relations with the US government.

The hostages, who could hear air strikes nearby and in at least one prison, were ordered to pray five times a day and were blindfolded even when moved between cells by the British gang.

‘Those guards really want everything to stay secret,’ one hostage told a friend. ‘They used lots of tricks to make sure we didn’t know who they were or where we were.

‘For example, when they entered the room, you faced the wall even if they were masked.’

Western captives were seen as valuable commodities, sometimes being fed better than local inmates. ‘They might keep Americans for special occasions,’ said a Syrian bounty hunter hired to track down hostages. One local journalist kidnapped by IS and held in their stronghold of Raqqa said they were crammed 20 to 40 in a stinking cell under a municipal building.

He described watching the torture of a fellow prisoner by guards using electric shocks and sticks, while two fellow inmates were publicly executed in a nearby square.

Syrians have been executed by IS for ‘crimes’ such as homosexuality and witchcraft.

The British security services have drawn up a shortlist of suspects behind the murder of James Foley

IS kidnaps and buys hostages from other groups, while also raking off a fortune from oil sales. It has become extremely wealthy and well equipped; even captured soldiers in Iraq are held to ransom, with $1 million raised from just 20 troops in one recent case.

A security source with intimate knowledge of Syrian kidnap cases said hostage families were contacted by email with threatening demands for money. ‘In some cases, the negotiators added on fees when families stalled or weren’t able to produce the money,’ he said.

It is understood £8 million was paid to secure the freedom of four French hostages, including war reporter Didier Francois, with another £16 million handed over for the lives of seven other European journalists and aid workers.

‘They usually demand insane ransoms for people, then it gets lowered to a few million,’ said a Syrian source. All governments deny making payments, but an official Italian source privately admitted paying ransoms last week. Most of the cash comes from governments, although families and employers have also contributed.

One hostage said £3 million was paid to free an Italian journalist held with him. Italian diplomats are currently in the region trying to negotiate freedom for two female aid workers.

IS is copying tactics honed by rival terror groups. The New York Times last month revealed Al Qaeda and its affiliates took £75 million from kidnappings over the past six years, with £40 million handed over last year alone. Yesterday, the United Nations called for concerted action to save thousands of people trapped by the fanatics in the town of Amerli, about 100 miles north of Baghdad.

Most of the town’s 18,000 residents are Turkman Shia, descendants of Ottoman Turks seen as apostates by IS forces that have besieged them for two months. They are in a desperate state, with no electricity or drinking water and are running out of food and medicines.

ISIS has specialised in kidnapping journalists and aid workers to ransom, torture and even murder

Yet IS remains defiant, despite global outrage. A spokesman told The Mail on Sunday that the message from the Foley murder was that they would fight the US ‘by all means necessary – and not just by killing a journalist’ – following US air strikes.

Abu Obiada, a religious official with IS currently fighting on the frontline against Kurds in Iraq, said Foley was killed despite his innocence for the crimes of his country.

Alarmingly, he claimed the bloodstained group already had ‘sleepers’ ready to strike in this country.

‘Our message is to know that we have some people already in the UK and US who are ready to fight them there.’

‘We will attack anyone who stands in the way of an expansion of the Islamic State,’ he said. ‘There is no border we will stop at.’ Last night it was revealed that a British militant fighting for IS has been killed during a daring raid at a military air base in Syria.

Abu Saif Al Britani was among 70 Islamic State terrorists killed as the group attacked the Al-Tabqa airbase in Eastern Syria on Wednesday.

The IS attack on Al-Tabqa was expected for months, as it is the last Syrian army base left in the province of Raqqa.

On Friday, a photograph of Abu Saif’s dead body appeared on the micro-blogging site Twitter, posted by fellow IS terrorists. A tweet in Arabic described Abu Saif as a British Bangladeshi who was in Saudi Arabia teaching English.

Asbos for terrorists? No, let's tell them never to come back

By DAVID DAVIS

British governments have historically taken an approach to the so-called ‘war on terror’ that has been distinctly un-British – crude, heavy-handed, careless of innocent people’s liberties, and as a result often counterproductive.

Yet our response to the flood of British Muslims that has left these shores to fight in Syria and subsequently Iraq for an Islamic caliphate has been tentative, uncertain, almost limp.

The brutal, ritualised public murder of James Foley has crystallised the psychopathic nature of what these young Britons have signed up to and in some cases actively promoted.

Conservative MP David Davis, pictured, believes that Jihad John and his friends should never return to the UK

The British intelligence agencies presumably knew what was going on. Yet the Home Secretary’s response as recently as yesterday seemed lacking in both focus and urgency. Asbos for terrorists? It is hard to imagine IS killers quaking in their boots over that.

So why have we done so little so far? We should target the young men who have rushed to take up arms on behalf of IS, an organisation that purports to be a state – and a hostile one at that. It is astonishing to me that this action alone is viewed as legal, let alone what they do once there.

Imagine that in my youth during the Cold War, I had gone off to join the Soviet Army with the intent of taking action against NATO, or that my father had gone to join the Nazis in the Second World War. Those actions would quite properly have been viewed as treason.

What these young men have done is worse. Remember that in this day and age even conventional ‘legal’ wars are essentially industrialised murder.

Civil wars, and the sort of sectarian conflict we are seeing in Iraq and Syria, are even worse, littered with the self-righteous sadism that we saw in the death of James Foley. They are wars without rules. And be clear. The barbarism we saw in the murder of Foley has been replicated time and again against thousands of innocent Iraqis and Syrians. Beheadings, crucifixions, burials alive have all been carried out against people guilty of no crime, largely for the purpose of feeding the IS propaganda machine.

David Davis said the young men are going to Iraq and Syria to participate in widespread murder and blackmail

These young men are going to Syria to take part in large-scale murder for an organisation with a $2 billion income from extortion, blackmail and theft.

So if it is not illegal already – hard to believe – let us make it so. Going abroad to fight and kill for a cause hostile to Britain and its NATO allies should be against British law and should carry a very heavy sentence. But I would go further than that. Since these young men are in effect swearing allegiance to a hostile state, they should all forfeit their British citizenship – not just those who are dual nationals. Since this is an incredibly serious penalty, it should be done only after a proper public trial carrying all the public seriousness and opprobrium of a murder trial, because in many cases that is what it would be.

As the Home Secretary reiterated yesterday, lawyers would say you cannot render someone stateless. Perhaps, perhaps not. Whitehall lawyers have been wrong before. Democracies have a right to defend themselves.

IS is claiming to be a state. They can issue these young men with Islamic State passports if they so wish. It is not our problem that they would have trouble getting into any civilised country with them. Neither will it be our problem any more if ISIL ceases to exist.

We must face head-on the paradox that these men can burn their British passports on TV and deny their legal allegiance to Britain, yet our nation cannot say to them, in effect: ‘OK, never come back.’

The result would be that these young men would suddenly find their trip to Syria is no longer a short violent holiday but a life sentence to the lifestyle they claim to espouse, complete with Sharia law and a desert climate. We are at a moment of decision. We can change or clarify British law to make the evil actions of these young men illegal and to make the penalty fit the crime: expulsion from the society they claim to reject.

We can do this in British courts and in doing so proclaim to the world that we are a tolerant society, but that we will not tolerate sadism and murder in the name of religion.