WARNING, THE VIDEO CONTAINS GRAPHIC IMAGES
The video seems, for the first few seconds, like one of the now ubiquitous jihadist recruit videos from one of the terror-aligned groups in Iraq - professionally shot, calling for recruits, and extremely violent.
But then the video's message begins to change. "Come to the Islamic State and learn new skills, like blowing up mosques, crucifying and executing Muslims. Travel is inexpensive, because you won't need a return ticket." The message is accompanied by gruesome images of a suicide bombing in a mosque, crucifixions and bloodied dead fighters. It is the project of an American government initiatives 'Think Again, Turn Away' which aims to win back some of the territory on the internet battleground where the jihadists have been comprehensively winning.
Now the fight is going to the second front, cyber terrorism, and Britain will play a crucial role.
A cyber cell of British and American intelligence and security agents is being created to defeat online attacks in an "unprecedented" deal to be struck by David Cameron and Barack Obama in talks at the White House today.
A rolling programme of war games will be staged across the Atlantic starting with attacks on the City and Wall Street to test their resilience.
It comes as a report by government listening post GCHQ warns the computer networks of British companies are under attack on a daily basis by hackers, criminal gangs, commercial rivals and foreign intelligence services.
The US Central Command's had its Twitter and YouTube hacked this week with the perpertrators claiming to have valuable documents about service personnel, though that was later disputed. President Obama is also toughening up the American response in the wake of the embarrassing and damaging North Korean hack on Sony Pictures and the infiltration of Pentagon Twitter and YouTube sites.
Ahead of a meeting in the Oval Office, Cameron said: "Just as we have worked with our closest ally, the US, to protect our people and our countries from traditional threats, so we must work together to defend ourselves from new threats like cyber attacks.
"This is an evolving threat which poses a real risk to our businesses and that's why we're taking our cooperation with the US to an unprecedented level. This is about pooling our effort so we stay one step ahead of those who seek to attack us.
"The joint exercises and training of our next generation of cyber experts will help to ensure that we have the capability we need to protect critical sectors like our energy, transport and financial infrastructure from emerging threats."
Under the plans GCHQ and MI5 will join forces with NSA and FBI to turn an American cyber cell into a transatlantic operation, to improve information sharing about threats.
Simulated attacks will be carried out to test systems, with institutions in the financial sector, including the Bank of England and a number of commercial banks being put to the test later this year.
A new generation of cyber agents will be trained up and a new Fulbright Cyber Security Award created to allow the most talented researchers to carry out research placements for up to six months.
Cameron has pledged to give security services more powers to monitor online exchanges between terror suspects and will raise the problem of terrorists using social media firms to plot in today's talks.
He told reporters that potential police murders had been spotted and prevented through use of communications data.
"Lots of attacks have been prevented," he told ITN. "We've had, since I've been Prime Minister, a major attack stopped every year. In the last few months a whole series of more minor attacks, the potential murders of police officers have been spotted. And on many occasions either communications data - who was calling who from where and when - has been vital or an intercept itself has been vital."
The Prime Minister said there was a broad agreement between Britain and the US over the powers needed to deal with terrorists communicating online. "We face the same challenge in Britain and in America," he told Sky News. "There is a broad agreement that we need to have the powers, in extremis, to intercept communications between terrorists. That is what America does today. It is what Britain does today.
"We share the intelligence and information between us and this has saved countless lives, not just in Britain and America but in other countries as well."
Cameron said the British system had "huge safeguards against intrusion" into privacy. He added: "I believe the British public will back me when I say that we shouldn't allow terrorists to talk to each without being able, in extremis, with a warrant from the Home Secretary signed personally by her, to intercept those calls."