A Palestinian human rights group is making a fresh attempt through the courts to force the British government to adopt sanctions against Israel.
The West Bank-based Al Haq wants a ruling that Britain is in breach of its human rights obligations by failing to take action.
The group, represented by the Birmingham-based Public Interest Lawyers, lost an application for a judicial review to hear its case in the High Court last year.
But an appeal, which will be contested by the Foreign Office, was due to begin in the Court of Appeal yesterday.
The group argues that Britain has violated international law by failing to take measures to stop Israel building settlements in the West Bank or causing civilian deaths in operations such as Cast Lead in Gaza last year.
It wants the UK to suspend arms-related exports to Israel; to press the EU to suspend its preferential trading agreement with Israel; and hand over evidence of alleged Israeli war crimes to British police.
The Palestinian General Delegation, which represents the Palestinian Authority, urged supporters to pack the courtroom so the case would have to be moved to a larger court with the hope of gaining "wider media attention".