Britain’s main opposition parties demanded Wednesday that the Conservative government publish legal advice it has received on whether Israel has broken international humanitarian law during the war in Gaza. They say the U.K. should ban weapons sales to Israel if the law has been broken.

       Britain is a staunch ally of Israel, but relations have been tested by the mounting death toll of the almost six-month war. Calls for an end to arms exports have escalated since an Israeli airstrike killed seven aid workers from World Central Kitchen, three of them British.

       David Lammy, foreign affairs spokesman for the main opposition Labour Party, said “there are very serious accusations that Israel has breached international law.”

       He urged the government to “publish the legal advice now.”

       “If it says there is a clear risk that U.K. arms might be used in a serious breach of international humanitarian law, it’s time to suspend the sale of those arms,” Lammy told British broadcasters

       London Mayor Sadiq Khan, one of the country’s most senior Labour officials, said “I don’t understand any justification for not publishing the legal advice that they’ve got.”

       “It’s important they publish that legal advice so that we can have confidence that the British government is following international law as well,” Khan told reporters in London.

       Two smaller opposition parties, the centrist Liberal Democrats and secessionist Scottish National Party, called on the government to halt arms sales to Israel.

       Prime Minister Rishi Sunak did not commit to publishing the legal advice, but said the U.K. followed a strict “set of rules, regulations and procedures” over licensing arms exports.

       “I have been consistently clear with Prime Minister (Benjamin) Netanyahu since the start of this conflict that while of course we defend Israel’s right to defend itself and its people against attacks from Hamas, they have to do that in accordance with international humanitarian law, protect civilian lives — and sadly too many civilians have already lost their lives,” Sunak told The Sun newspaper’s politics podcast.