For several years now, British faculty unions have been voting in various ways to encourage members to boycott Israeli academics and universities -- and ignoring anti-boycott pleas and resolutions and requests from scholarly societies, university presidents and academics from Britain, the United States and in some cases the Palestinian Authority. On Friday, the union announced an abrupt reversal: Based on legal advice, calls for the boycott will be dropped.

A statement from the University and College Union said that after the latest vote by union leaders, in May, the group's leaders sought legal advice to make sure the organization wouldn't face court challenges. The lawyers said that pushing for a boycott would be illegal. "It would be beyond the union's powers and unlawful for the union, directly or indirectly, to call for, or to implement, a boycott by the union and its members of any kind of Israeli universities and other academic institutions; and that the use of union funds directly or indirectly to further such a boycott would also be unlawful," the lawyers said. As a result, the union is calling off plans for a tour of local chapters to encourage them to support a boycott.

Technically, the latest version of the measure to isolate Israeli academics -- adopted in May -- was in fact a call for a boycott, rather than a boycott. Delegates to the union's convention voted to circulate to members and divisions a resolution calling for an academic boycott of Israel. Proponents of the boycott said that Israel's treatment of Palestinians rose to the level that deserved not only international censure, but the isolation of universities and academics, whom boycott advocates said are complicit with Israel's government. Leading supporters of the boycott did not respond to requests for their reaction to the latest news, nor did they update Web sites that they have maintained to make the case for a boycott.

Sue Blackwell, one outspoken advocate of the boycott and a professor at the University of Birmingham, said to The Guardian of the union's decision: "It is quite ridiculous. It is cowardice. It is outrageous and an attack on academic freedom."

British faculty unions do not have the power to enforce a boycott and from the start, some professors have ignored the movement and continued ties to Israel. But others have not and some Israeli scholars have been told over the years that, for example, their editorial contributions are no longer needed at certain journals edited by boycott leaders.

The boycott calls in their various forms have brought strong denunciations from academic groups. They have noted that generally accepted principles of academic freedom are based on the value of ongoing scholarly communication around the world, that other means exist to protest the policies of Israel's government, and that many Israeli academics are among the leading critics of their government's policies.

Some pro-boycott British academics have said exceptions would be made for selected academics, but academic freedom experts have said that would be even more troublesome in that it would establish political litmus tests for academics to meet to avoid a boycott. While pro-Israel groups have organized much of the opposition, the revulsion of the idea of an academic boycott is strong even among groups without great love for Israeli leaders. The Middle East Studies Association, for example, which has protested numerous Israeli actions, in 2005 came out against a boycott as antithetical to academic freedom. "We especially oppose penalizing entire segments of an academic community for any reason whatsoever," a letter from the association said.

Ofir Frankel, executive director of the International Advisory Board for Academic Freedom, a group formed to oppose the boycott movement, issued a statement welcoming its end. "The UCU has realized at last that an academic boycott is not a legitimate means of political protest," Frankel said, adding that ties between Israel and Palestinian scholars, and those from other countries, should expand, reflecting the way "academicians were always [at] the vanguard of change and bringing about of peace."