Tuesday's talks are to focus on Palestinian institutional reform but not on the international peace process - as Israel's absence rules out any political breakthroughs, British officials said.
But Palestine's deputy foreign minister, Abd Allah Abd Allah, said Abbas was also very reluctant to go to London, fearing the meeting was designed to raise political hurdles that will serve Israel's interests.
"There was grave concern about what this meeting was about. But we are demonstrating our interest by sending a very high level delegation," he said.
"The initial thought of the conference was more of a political nature, a peace conference. But you need two to tango. The Israelis are not there so the British thought of a more modest meeting with a less ambitious agenda," Abd Allah added.
Nevertheless, the Palestinian Authority (PA) has indicated it was hopeful the London conference would reinforce international pressure on Israel to push the peace process forward.
Palestinian Planning Minister Ghassan al-Khatib told Aljazeera the talks will persuade the international community "towards the implementation of Israel's withdrawal form Gaza, and to highlight the commitment of all the parties concerned to return to negotiations".
But critics were not so sure.
"The donors will promise aid but attach conditions and apply pressure on the Palestinian Authority for reform, particularly security reform"
Professor, Beir Zait University
Ali al-Jirjawi, a professor at Bir Zait University, told Aljazeera: "There is no direct political benefit [from this meeting]. This meeting will focus on the Palestinian Authority and not a political settlement.
"The donors will promise aid but attach conditions and apply pressure on the Palestinian Authority for reform, particularly security reform."
Al-Jirjawi further said: "Israel's absence will - with no doubt - cast a shadow over the meeting, as it is a partner in any peace process and its absence spares it from any commitments.
"In addition, this government is the main cause of the Palestinian economic crisis. The Palestinian economy would have been intact had it not been for the actions of this government."
Israeli government spokesman Avi Pazner said
: "The aim of this conference is to promote internal reform within the Palestinian Authority and that is why Israel is not participating."
He denied reports on Israeli radio that the government was displeased about the conference.
Representatives of the World Bank and International Monetary Fund are also attending and members of the Middle East Quartet - Russia, the European Union, the UN and the US - will meet on the sidelines of the conference.
British officials expect some countries to pledge cash to plug short-term gaps, setting the stage for a donor conference by the end of June.