After three deadly terror attacks over the past week - in Tel Aviv, Orlando and Magnanville - British security experts have warned that the principal danger posed to the Jewish community comes from similar lone wolf terrorists or small cells.
During Shavuot, police patrols in Jewish neighbourhoods in London were increased to provide greater security after the shootings at the Max Brenner restaurant in Tel Aviv last Wednesday night.
The Community Security Trust said tackling the threat from individuals or small cells is key to protecting the community and has "long been an integral part of our planning".
Mark Gardner, CST communications director, said jihadi groups were urging supporters to "go out and commit random acts of terrorism.
"The spread of social media now makes such calls even more widespread and dangerous than before.
Attackers have a presence on Facebook and Twitter
"It's part and parcel of modern terrorism and we need to protect against that risk; a situation in which anybody at any time and place can commit a violent act and declare it as being part of the wider ideological goals and practices of an established terrorist organisation or movement."
The controversy in American politics and media over how to define the massacre in Orlando, where a lone gunman killed 49 people at the Pulse nightclub and wounded 53, has underlined how difficult it is for security services to deal with "lone wolf" attacks.
Some have said it was both an Islamist terror attack and a homophobic hate-crime. Others have said it was just one of those - or even neither, stressing the role of America's deadly love affair with guns.
Certainly, every murder is based on both personal frustrations and specific local factors. But radical religion and ideology amplify these, and act as a powerful motivator for violence and suicidal missions.
On the eve of Ramadan last week, Daesh's leadership urged its supporters in the West to carry out independent attacks, as Omar Mateen did in Orlando on Sunday, and as Larossi Abballa, who stabbed to death a police officer and his partner on Monday night, did in Magnanville (near Paris). Both were able to die in a hail of bullets as 'soldiers' of Daesh.
These attacks are very different from those which took place in March in Brussels and last November in Paris. To achieve an impact, Daesh then used its extensive network of terror cells, communications, logistics and local collaborators to carry out operations which were directed by the leadership in Raqqa, Syria.
The attacks this week, like last December's in San Bernardino, can more accurately be described as attacks by individuals inspired by Daesh. As such, they are much more difficult to detect and prevent using traditional intelligence methods.
This is particularly worrying in the US, where the availability of weapons lowers the logistical threshold for carrying out mass murder.
It is a similar challenge to that faced by Israel's security services over the last year with what some military officials call "the individuals' intifada".
How does one detect an attacker working on his or her own, radicalised and encouraged online but without any even casual connection with a network?
This has been true of nearly all the hundreds of Palestinian civilians who attacked Israelis in recent years, virtually invisible to intelligence agencies whose tried-and-trusted strategy for decades has been to infiltrate, disrupt and break up terror networks.
New methods to contend with this change are still evolving but one which is proving successful is using the tool of radicalisation - social media - as a counter-terrorism tool. The attackers have a social media presence, usually on Facebook but also on Twitter and Instagram. Analysis of their behaviour online has yielded profiles of potential attackers and, in many cases, also the additional motivations for a suicide attack. Often these are personal and non-ideological reasons such as debt or forced marriage.
In many cases, Israeli security services believe the real motivation behind attacks was the desire for "suicide by IDF", attaining the status of martyrdom and sparing family embarrassment.
New watch-lists have been compiled, potential attackers and their families have been warned, and in some cases high-risk suspects have been located and apprehended on the way to carry out an attack.
No counter-terror method is foolproof, but online surveillance and profiling is now the name of the game in preventing future lone-wolf attacks.