A former UK foreign minister has written an open letter to Foreign Secretary William Hague calling on the British government to pull out of next month's conference to mark the tenth anniversary of the Durban declaration on anti-racism. This document singled out Israel as the only perpetrator of human rights abuses.

Denis MacShane, who attended the original conference in South Africa, said the conference and its follow-up in Geneva in 2009 "provided a platform for the most egregious expression of Jew-hatred seen on the international stage so far this century".

The World Conference Against Racism, Racial Discrimination, Xenophobia and Related Intolerance will take place just as the UN General Assembly considers a possible unilateral declaration of independence (UDI) by the Palestinians.

Dr MacShane, who was a Foreign Office minister from 2001 to 2005 under Jack Straw, said: "With hindsight I wish that Straw and his ministerial team, including myself, had had the guts to pull the UK out of the Durban 1 conference, and send a clear signal."

Dr MacShane also attended the Geneva conference two years ago when Iran's President Ahmadinejad stated that the Holocaust was "an ambiguous and dubious question".

Several countries, including Israel, America, Canada, Italy, the Netherlands and the Czech Republic have already pulled out of Durban III. The UK has so far decided to remain within the drafting process of a new anniversary declaration. The Jewish Human Rights Coalition has called on Britain to pull out.

There is concern in pro-Israel circles that a new statement from the anti-racism conference targeting Israel would provide ammunition to those pressing for Palestinian UDI.

At the same time, UK Jewish leaders are keen not to let Durban III become a distraction from the September vote in the General Assembly. "We don't want the government to do the right thing on Durban III and not on UDI," said one senior source.