The newest and least attractive import from America, following on behind Coca-Cola, McDonald's and Friends, is the pro-Israel lobby. The latest target of this US-style campaign is the august Oxford Union.

This week, two Israeli colleagues and I were due to appear at the union to participate in an important debate on the one-state solution in Israel-Palestine. Also invited was the American Jewish scholar and outspoken critic of Israel, Norman Finkelstein. At the last minute, however, the union withdrew its invitation to him, apparently intimidated by threats from various pro-Israel groups.

The Harvard Jewish lawyer and indefatigable defender of Israel, Alan Dershowitz, attacked the topic of the debate as well as the Oxford Union itself. In an article headlined "Oxford Union is dead", he accused it of having become "a propaganda platform for extremist views", and castigated its choice of what he termed anti-Israel and anti-semitic speakers.

Yet Dershowitz could have restored the balance as he saw it; he was the first person invited by the Oxford Union to oppose the motion but he declined due, as he put it, to "the terms of the debate and my proposed teammates".

Dershowitz's article attacking the Oxford Union appeared in the Jerusalem Post in Israel and Frontpage magazine in the US. [Because of British defamation laws Cif has been advised not to provide a link - Ed.]

Dershowitz and Finkelstein were protagonists in a much-publicised academic row in the US, though it is unclear whether this has any relevance to the Oxford Union spat.

In solidarity with Finkelstein and to oppose this gross interference in British democratic life, the three of us on the "one state" side - myself, Avi Shlaim, of St Anthony's College, Oxford, and the Israeli historian Ilan Pappe - decided to withdraw from the debate. This was not an easy decision, since the topic was timely and necessary given the current impasse in the Israeli-Palestinian peace process, where innovative solutions are in short supply.

Dershowitz and the other pro-Israel activists may rejoice at their success in derailing an important discussion. But it is of little comfort to those of us who care about freedom of speech in this country. Last May, Dershowitz interfered in British academic life when the University and College Union voted overwhelmingly to debate the merits of boycotting Israeli institutions. He teamed up with a British Jewish lawyer, Anthony Julius, and others, threatening to "devastate and bankrupt" anyone acting against Israeli universities.

In another example of these bullying tactics, the Royal Society of Medicine, one of Britain's most venerable medical institutions, came under an attack this month, unprecedented in its 200 year history. It had invited Dr Derek Summerfield, a psychiatrist (who has also documented Israelıs medical abuses against Palestinians in the Occupied Territories), to its conference on Religion, Spirituality and Mental Health. The RSM was immediately bombarded with threats from pro-Israel doctors demanding Dr Summerfield's removal on the grounds that he was 'political' and biased, and that the RSM's charitable status would be challenged if he remained. Intimidated, the RSM asked Dr Summerfield to withdraw, although they later reinstated him.

The power of the Israel lobby in America is legendary. It demonstrates its influence at many levels. Campus Watch is a network that monitors alleged anti-Israel activity in US academic institutions. The difficulties of promotion in the US for scholars deemed anti-Israeli are notorious. The notable Palestinian academic, Edward Said, was subjected to an unrelenting campaign by pro-Israel groups at Columbia University with threats on his life. His successor, Rashid Khalidi, is the current object of the same campaign of vilification and attack. Finkelstein himself has been denied tenure at his university and everywhere else. The authors of a recent study of the Israel lobby's influence on US foreign policy have been called anti-semites and white supremacists. Former president Jimmy Carter's book, Palestine: peace not apartheid, has earned him the label of "Jew-hater" and Nazi sympathiser. The British publisher, Pluto Press, is likely to be dropped by its American distributors, the University of Michigan Press, because pro-Israel groups accuse it of including "anti-Semitic" (ie pro-Palestinian/critical of Israel) books on its list.

Such activities are familiar in the US. People there are hardened or resigned to having their freedom of expression limited by the pro-Israel lobby, and the threats of Dershowitz would cause no surprise to anyone. But Britain is different, naively innocent in the face of US-style assaults on its scholars and institutions. No wonder that those who have been attacked give in so quickly, nervous of something they do not understand. The UCU leadership, shocked and intimidated by the ferocious reaction to the boycott motion from pro-Israel groups, resorted to legal advice to extricate itself and announced in September that a call to boycott Israeli institutions would be "unlawful". The Oxford Union jettisoned one of its participants rather than stand up to the threats of its critics. The RSM tried to distance the offending speaker from its conference to protect itself from abuse.

All this is understandable, but it is exactly the wrong response. Appeasing bullies like Dershowitz will not stop them. It will rather encourage them to go further. The question is, do we in this country want a McCarthyite witch hunt? If not, then we must confront the bullies and expose them for the intellectual terrorists they are, bent on destroying the values of a free society. To do otherwise will invite the fate of all repressed people, cowed and intimidated, hating their tormentors, but too afraid to say so.