Israeli architects have appealed to David Cameron to intervene in the row over British efforts to have them thrown out of their international union.
The Israeli Association of United Architects (IAUA) has also approached Israel’s Foreign Ministry for assistance.
Royal Institute of British Architects (Riba) members last week voted through a proposal by its former president Angela Brady urging the International Union of Architects (IAU) to suspend Israeli members until “illegal projects” in the West Bank cease.
Itzhak Lipovetzky, head of foreign relations at the IAUA, said: “When the British prime minister was here, he promised not to boycott Israel. This was his statement in front of the Knesset.”
Riba’s move was condemned by the British Council, which said the motion did not reflect the views of the profession.
Vicky Richardson, the Council’s director of architecture, design and fashion, said: “Many architects rightly see this as divisive and unhelpful.
"It's better to let architects choose who they want to work with and keep international links and communication open. Boycotts close off discussion and debate."
Stephen Games, founder of the New Premises architecture think-tank, said Riba would face calls for it to be stripped of its royal charter as a result of its actions.
Mr Games wrote to Riba president Stephen Hodder following the vote and described the institute’s actions as both “antisemitic” and a “disgrace”.
“The Riba is not a political body, it has no special insight into the dispute, nor is there anything in its constitution that should lead it to be partisan. The proper role is to preserve neutrality. To do otherwise is to act outside its mandate as a royal body,” wrote Mr Games.
He said the organisation risked “emerging not as a body that supports Palestinians but as a body with an in-built and unprincipled prejudice against Israel and legitimate Jewish aspiration”.
Riba denied the organisation was “in any way antisemitic” and said in a statement that its international committee would discuss the issue with the IAUA “in order to better understand its position on this important matter”.
Mr Hodder is expected to meet Mr Games and pro-Israel architects next month.
Shimon Samuels of the Simon Wiesenthal Centre wrote to the IAU claiming Riba had “allowed itself to become the victim of an extremist group of spoilers that use tactics redolent of the Nazis' 1930s boycott campaign”.
He questioned why similar action had not been taken against IAU members from countries with poor human rights records and ongoing political disputes, including China, North Korea, Sudan and Turkey.
Dozens of British architecture firms work in those countries. Riba itself signed an agreement with two Libyan groups earlier this month.
Dr Samuels said the IAU should reject Riba’s campaign and avoid being “hijacked by political agitators”.
The Royal Incorporation of Architects in Scotland passed a similar motion the week before Riba.
Abe Hayeem, chairman of Architects and Planners for Justice in Palestine (APJP), which supported the motion, said Riba and Rias had “sent a clear message and struck a blow for the integrity and ethical practice of our profession”.
The IAU did not respond to requests for clarification on whether it would suspend Israeli members, or what action it would now take.