The UK should stop arming Israel in order to comply with the historic advisory opinion by the UN’s top court that member states should not “render aid or assistance” to the occupation of the Palestinian territories, a lawyer who represented Palestine has said.

In a broad and damning ruling published this month, the International Court of Justice (ICJ) found that Israel’s settlement policies and occupation of the territories were in breach of international law. It also said UN member states were under an obligation to neither recognize the occupation as lawful nor abet it.

With the UK already under pressure over the sales of arms to Israel during its military offensive in Gaza, which has killed almost 40,000 Palestinians, Prof Philippe Sands KC, a member of Palestine’s legal team for the case at the ICJ, said the court’s opinion had important ramifications for the UK.

“The most immediate issue is the obligation in the advisory opinion on the states, which includes the United Kingdom, not to aid or assist in the maintenance of the current situation in the occupied territories of the West Bank, including [East] Jerusalem,” said Sands.

“That legal obligation precludes sales of military material which could be used directly or indirectly to assist Israel in maintaining its unlawful occupation of the occupied Palestinian territories.”