The British Committee for the Universities of Palestine (Bricup) has claimed its campaign led TV botanist David Bellamy to pull out of a Zionist Federation science event.
Prof Bellamy was scheduled to be guest speaker at the Israel Blue White and Green event last week, but withdrew offering no explanation for his absence.
The JC understands that the ZF is now considering taking legal action against Prof Bellamy for breach of contract.
Bricup's Jonathan Rosenhead said there was a "reasonable inference that his withdrawal is related to our letter to him asking him to do so". Nevertheless, he admitted that the organisation had not had a response from Prof Bellamy.
Bricup supporters including Lord Ahmed and Baroness Tonge had earlier written to the botanist and academic saying he should be "outraged" by the "greenwashing of the occupation".
Prof Bellamy's agent, Olivia Guest, this week again declined to clarify why he had not attended the event.
Naomi Wimborne-Idrissi, secretary of Jews for Boycotting Israeli Goods, (JBIG) was evicted from the session with Israeli scientists after shouting questions about Israel not allowing Palestinians fair access to water. She claimed she was "physically dragged out of the meeting" by CST security staff and "frog-marched up the stairs".
A second JBIG activist said he had been "carried out" by CST. The pair said they were considering getting legal advice over the evictions.
But a CST spokesman said: "Bricup's claims are exaggerated and untrue. Nobody was 'carried' anywhere."
Alan Aziz, ZF director, said: "Two people were making speeches and shouting. People asked for them to be removed, we decided to remove them and CST carried out our wishes."
He said discussions with Prof Bellamy' agents were continuing.