The Foreign Office was facing a battle to stave off a parliamentary defeat after the Board of Deputies of British Jews said it was backing calls for the British courts to be given a new role in determining if the Uighur people are suffering genocide in China. Dominic Raab, the foreign secretary, is seeking to overturn an all party amendment passed in the Lords giving victims of genocide the power to ask the UK high court to determine if genocide is taking place. Such a determination would require the government to consider pulling out of any free trade agreement. The amendment, being presented as a test of the importance of human rights in post Brexit-trade agreements, will be considered by MPs when the trade bill returns to the Commons on Tuesday. But the Board of Deputies revealed they were writing to all MPs to back the measure. Phil Rosenberg from the Board of Deputies said: “This should not be a partisan issue, but an issue of natural conscience. I cannot underscore enough the importance we place on this issue and this amendment.” He reported the president of the Board, Marie van der Zyl, had written to the Chinese ambassador to the UK. Her letter said: “Nobody can fail to notice the similarities between what is alleged to be happening in the People’s Republic of China today and what happened in Nazi Germany – people being forcibly loaded on to trains, beards of religious men being trimmed, women being sterilised and the grim spectre of concentration camps.” The amendment, passed by the Lords with a majority of 129, has the backing of all the opposition parties, including the Labour frontbench, so Raab is working to keep the Conservative rebellion below 40 of his own MPs to see off the measure. The rebellion is said to be gaining support, but is thought to be a handful shy of the numbers needed to defeat the government. The foreign secretary believes the measure will lead to vexatious court claims and may prove counterproductive since the threshold to prove genocide is so high. Genocide is defined as a deliberate attempt to destroy a race on the basis of their ethnicity or religion. But the Tory leader of the rebellion, Iain Duncan Smith, said: “If we do not speak for those who are benighted and trashed by authorities then we do not deserve to be in the mother of parliaments.” Nusrat Ghani, the Conservative MP for Wealden, said the amendment was appropriate for a country starting off on a new phase in its history, adding the UN system for determining genocide, such as the international criminal court, was broken due to China’s use of its veto. “We are consuming goods made by the Uighur people in prison camp circumstances,” she said. Lisa Nandy, the shadow foreign secretary, insisted she would not allow the treatment of the Uighur people to become a partisan issue saying it is “a scar on the conscience of the world”. But she insisted the government needed to back its tough words with more specific action. Rahima Mahmut, the Uighur activist said she accepted rebellion is difficult, but anyone that votes against the amendment could not count themselves as friends of the Uighur people. Tom Tugendhat, the chair of the foreign affairs select committee, said the UK needed to make a stand adding “the UK was having to fight slavery again for the first time in hundreds of years, but this is a battle that has come to people’s homes and shops”. Raab this week tried to stave off the rebellion by announcing measures to tighten up supply chains of companies operating from Xinjiang province, but critics say his measures are tame in comparison with steps announced this week by the US state department.