Pro-Israel groups have responded too slowly to the impending parliamentary vote on Palestinian statehood and have lost valuable campaigning time, activists have admitted.
There are concerns that a tardy response from Jewish communal organisations has paved the way for a "propaganda coup" for pro-Palestinians next week.
Pro-Palestinian MPs will lead a debate in the House of Commons on Monday, calling on the government to immediately recognise Palestine as a state.
Almost two dozen MPs who support Israel have tabled an amendment, calling for the formation of a Palestinian state only after a formal peace deal between the Israeli government and Palestinian Authority.
The We Believe in Israel group urged supporters last week to make the case for a negotiated two-state solution to their parliamentary representatives.
We didn't recognise the significance of the motion
But pro-Palestinian groups claimed more than 23,000 activists had already contacted their MPs by that stage.
One campaigner helping to co-ordinate the community's reaction told the JC the response had been slow off the mark, with activists and leadership groups pre-occupied by the party political conferences. There has also been disagreement over how to frame opposition to a unilateral Palestinian declaration of statehood.
"We didn't recognise the significance of it. MPs were calling and saying 'wake up'. But there was not 100 per cent agreement among communal groups on how to deal with it," the source said.
The activist said MPs backing the motion had been "very clever. The motion is very blandly worded and could be interpreted as being supportive of a two-state solution, which all key groups here support".
If successful, Monday's motion will not change the government's approach to Israel and the Palestinians. Both the Foreign Office and Labour's Shadow Foreign Secretary Douglas Alexander have said negotiations between the sides should precede the formation of a Palestinian state. But a victory in the Commons would provide a propaganda coup, pro-Israel campaigners said.
The United Synagogue was among the groups encouraging its members to lobby MPs. Its pre-Yom Kippur message to congregants led on the issue. The Board of Deputies issued a "call to action" on Monday, saying there was a risk of a "significant PR victory for anti-Israel, anti-peace groups".
Grassroots group Israel Advocacy UK said it had had more than 400 people sign a petition appealing to MPs to back the amendment.
Davis Lewin, deputy director of the Henry Jackson Society think-tank, said the vote was "not what it looks like in terms of peace-making. It is important that the amendment succeeds.
"The campaigners driving this are interested in the destruction of Israel."
He said he would brief MPs on the danger of a unilateral declaration of statehood before the vote.