Inside the SOAS auditorium, after a meticulous security check, the students waited - with kaffiyeh headdresses, prepared questions, and a desire to have the Palestinians' voice be heard before an official representative of Israel.
"We wanted to bring the ambassador right into the lion's den," the British Zionist Federation organizers said, "and he readily consented."
Before the proceedings began, the host made an announcement: "The ambassador has asked me to say that the tougher and hard-hitting the questions are - the better."
Israeli PR efforts in Britain have kicked up a notch since Prosor became ambassador two months ago. As a former Foreign Ministry director general, he is focusing on speeches to new kinds of audiences, frequent television appearances and press interviews.
"I'm not afraid to appear anywhere, and there is no platform - suitable of course - that I will not utilize for PR work," Prosor says.
Among other venues, he delivered a speech at St. Antony's College, Oxford, the day after that institution invited Holocaust denier David Irving to speak.
Prosor says he wants to influence British public opinion, which he says is more extreme than the political establishment in its criticism of Israel, and hugely influential.
"If something remains of the British Empire's power in the world, it is the British media's impact," he says.
This is what brought the ambassador to address a capacity-crowd at SOAS. The students sat in the gallery, while the Zionist Federation's invitees sat below.
"I am here to present the arguments for Israel," Prosor said at the outset, before answering the students' questions.
These were mostly critical: Do you believe that Israel's actions constitute international war crimes? Do you think there will be something like the Nuremberg Trials for Israelis involved in the conflict, or that there will be truth and reconciliation committees like in South Africa? Why do you designate Hamas as a terror organization and reject dialogue, when Menachem Begin and Yitzhak Shamir were terrorists themselves? Do you even believe the words you're saying here? - the latter question prompting applause from the gallery.
Prosor gave answers, while repeating Israel's main PR points: the difficulty of contending with suicide bombings, former prime minister Ehud Barak's generous offer to Yasser Arafat in 2000 and "the fact that the Israeli public has moved leftward in recent years whereas the Palestinians have moved to the extreme right."
Applause from the lower part of the auditorium greeted his declaration that "Jerusalem shall remain the capital of Israel forever."
"If there is one thing I want you to take home with you it is this: Israel is a democracy under attack that is dealing with difficulties that no other country is facing," Prosor concluded.
He estimates that most Britons believe that "the Israeli-Palestinian conflict is a clear case of David versus Goliath," as one unconvinced student said afterward. He therefore considers it his job - among other things - to place the conflict within a broad context and present the complexity of life in Israel. He doesn't worry about legitimizing Israel-bashers by parrying their claims.
"You've got to consider the alternative - If I don't show up, the vacuum I leave will be filled by someone else," he says. "So I will go to universities, to trade unions, to relevant conferences. So long as somebody gives me a platform - I will come.