But what about the protection of synagogues in the UK? Terrorism expert Dr Hans-Jakob Schindler from the Counter Extremism Project explains that some protective measures did work in Manchester - for example, the attacker was unable to enter the synagogue and the police were probably "extremely quick on the scene". However, what did not work and now needs to be investigated is the lack of barriers around the synagogue, especially for traffic, explained Schindler. Given the large Jewish community in Manchester, it would have been natural to assume that significantly more worshippers would come to the synagogue on Yom Kippur than on normal days, says Schindler.