A Conservative backbench rebellion designed to give the UK courts a role in determining whether a country is committing genocide appears to have been frustrated by what rebels claimed was government chicanery and a denial of democracy. Ministers arranged Tuesday’s vote so that if the rebels back an amendment passed by the Lords giving the court a role, they will also be backing a separate Labour-sponsored amendment passed in the Lords imposing human rights audits before trade deals are signed. Some Tory MPs are prepared to rebel to give the courts a role, but not if by so doing they are also backing the Labour-sponsored plan. One leading campaigner for what has become known as the genocide amendment complained: “Peers voted on the two distinct propositions separately so it is not clear why the clerks regard it acceptable to treat the MPs’ endorsement of one Lords amendment as endorsement of the other. They should not be bundled together. It is not even a parliamentary trick, it is a denial of democracy.” The campaign to give the UK courts an advisory role in declaring if a country is committing genocide has drawn passionate support outside parliament, and is driven by allegations that Uighur Muslims are suffering a genocide at the hands of the Chinese government. The genocide claims cannot be referred to the international courts due to a Chinese veto, so campaigners wanted a right to refer the issue to the domestic courts. Iain Duncan Smith, the lead Tory rebel, said: “The sad tragedy is that the government has so engineered it that the democratically elected House of Commons will not be able to vote on Lord Alton’s genocide amendment, which passed in the Lords with a majority of 171”. Nus Ghani, another Tory rebel MP, said she was “appalled at the parliamentary games played over an issue as grave as genocide”. Benedict Rogers, the chief executive of Hong Kong Watch, described the tactics as outrageous, adding: “I have never seen a government so afraid to do the right thing.” It is now likely MPs will back a government-backed compromise designed to give the foreign affairs select committee, and a parallel committee in the Lords, powers to investigate whether a genocide is occurring, and then to make a recommendation on whether a government trade deal should go ahead. Ghani complained: “A select committee can already prepare a report on genocide and the offer is meaningless since genocide can only be determined by a judicial process.” She added that majorities on both the foreign affairs select committee and the Lords’ international relations select committee did not want to be given the role, if there was no power to refer the issue to the courts. Lord Alton, an independent peer, said: “Both select committees in the Commons and Lords have said they would not wish to take on this role without having the opportunity to then refer the issue to the high court. It would take up a huge amount of time, energy and effort.” He said he did not think MPs were as impartial or as appropriate as judges in determining such complex issues. The issue has also become a test for the government’s policy towards China, a policy made more difficult by the US’s recent decision asserting that China is committing genocide against Uighur Muslims in Xinjiang province. Ministers have also warned peers that the proposal might create diplomatic difficulties. MPs rejected a role for the courts in determining genocide by a wafer-thin margin of 11 votes last month, but since then, peers reasserted their support for the measure by a huge majority of 171, forcing the government whips in the Commons to put the squeeze on their backbenchers for a second time. In a joint letter signed by 20 civilian groups including the Burma campaign, the World Uyghur Congress and Yezidi Emergency Support, the groups say the UK has played a key role in the past five years leading the fight to protect the Yazidis when Isis was trying to wipe them out, and a role for the UK courts in determining genocide could be the start of a new global atrocity prevention strategy. If the courts were given a determination role, it would still be up to ministers to determine whether a trade agreement should be retained. Ministers say the proposal would give courts a role they do not seek and could backfire, since proof of genocide is such a high bar to overcome.