UK government agencies have broken the law by not investigating the importation of cotton products manufactured by forced Uyghur labourers in China, the high court has heard. The World Uyghur Congress (WUC) is challenging the home secretary, HM Revenue and Customs and the National Crime Agency (NCA), claiming a failure or refusal to investigate imports from Xinjiang, allegedly home to 380 internment camps, was unlawful. In London on Tuesday, Jenni Richards KC and Tom Forster KC, for the congress, said there were reasonable grounds to suspect breaches of criminal and civil law under the Foreign Prison-Made Goods Act 1897 and the Proceeds of Crime Act (Poca) 2002, which concerns money laundering. In written arguments, they said 85% of Chinese cotton was grown in the Xinjiang Uyghur Autonomous Region (XUAR); named four Chinese companies they said were involved “on a very large scale”; and detailed those firms’ connections to the UK. “It can and should be reasonably inferred from the evidence that the vast majority of the cotton manufacturing done in facilities operated by these companies in the XUAR is carried out by labourers subject to conditions of detention and forced labour,” they said. “Accordingly, if a UK company sources any cotton products from one of the implicated Chinese companies, there is a high risk that the product in question was produced (wholly or partly) by prison and forced labour.” In oral submissions, Richards went further, saying it was “inevitable” such cotton products emanated from detention and forced labour. Forster said that “well-known” UK companies, which he did not name, sourced products from three of the four Chinese firms identified. The lawyers said Poca “does not require the identification of a specific consignment of cotton products generated by forced labour that has entered the UK before a criminal investigation can even commence. The defendants’ stance defeats the very purpose of investigating the proceeds of crime”. Since 2014, when the Chinese government launched the “people’s war on terror” to gain effective social control over Uyghurs and other Turkic people, vast industrial parks for the manufacture of cotton had been constructed across Xinjiang as well as internment camps, where torture, rape and inhuman treatment had been documented, the court heard. Reasons for detention in camps include having a beard, wearing a veil, applying for a passport, praying, downloading WhatsApp and having too many children, the claimants say. Evidence indicates that the industrial parks are primarily staffed by labourers from “re-educated” groups of workers from the internment camps referenced and other groups of Uyghurs and other ethnic minorities also under duress, the court was told. James Eadie KC and David Perry KC, acting for the defendants, said in written arguments that the government considered China’s treatment of Uyghurs and other minorities in Xinjiang to be “appalling”. But they said the NCA’s position was that there was insufficient material to warrant a criminal investigation, although that position could change in the light of new information. In the absence of any error of law, they said it was not for the court “to interfere in the discretionary decision of law enforcement agencies as to whether to investigate in the present circumstances”. They added: “At best, the claimant’s case is that there is a compelling inference of a chance that a crime has been committed but it is unable to identify how, by whom, when, or where such an offence took place. The existence of a general statistical likelihood is not (nor has it ever been) a basis for any criminal investigation or the exercise of any coercive power.” The case is expected to conclude on Wednesday with judgment to be given at a later date.