The government has been criticised by its own Islamophobia adviser for refusing to publish the evidence behind Matt Hancock’s claim that people were “not abiding to social distancing” as he imposed a lockdown on 4.6 million people in northern England at the start of the Muslim celebration of Eid al-Adha. Qari Asim, the deputy chair of a government taskforce on anti-Muslim hatred, said the health secretary’s claim on Twitter added to “hateful narratives” and “gave the impression that Muslim communities were not social distancing and were ignoring the government guidelines”. Hancock made the remark in a late-night Twitter thread on 30 July, when Eid al-Adha started, announcing with three hours’ notice that strict restrictions would be imposed on Greater Manchester, parts of East Lancashire, West Yorkshire and Leicester from midnight. He said: “The spread is largely due to households meeting and not abiding to social distancing. So from midnight tonight, people from different households will not be allowed to meet each other indoors in these areas.” The lockdown, imposed 12 weeks ago and largely still in place, sparked a frenzy on far-right social media networks as extremists blamed Muslims for spreading the coronavirus. The timing and manner of the announcement was immediately criticised by police chiefs, MPs from all parties, and Muslim leaders who described it as “shameless scapegoating of Muslims”. Many of the northern cities and towns placed under lockdown have above-average south Asian populations. In response to a freedom of information request, the Department of Health and Social Care (DHSC) confirmed it held the evidence to support Hancock’s claim but refused to publish it. It said to publish the data would jeopardise “the internal deliberative process as it relates to policymaking”. Asim, a senior adviser to the government, urged ministers to publish the data immediately. He said Hancock’s claim “gave the impression that Muslim communities were not social distancing and were ignoring the government guidelines. Therefore it’s only right that full data is made public to make things clearer.” He added: “We saw a rise of Islamophobia online [in the aftermath of the announcement] and the Muslim communities were seen as the cause of another lockdown. Some people definitely felt that the timing of the announcement was very poor. The way it was made showed disregard to a faith community. “We don’t want to give rise to hateful narratives and it’s really import that the authorities ensure that such hateful narratives are not supported.” Hancock’s tweets came just hours after a high-level meeting had considered a report by a subgroup of the government’s Scientific Advisory Group for Emergencies (Sage) that said local lockdowns could lead to a “divided nation” and “be exploited by far and extreme rightwing groups”. It warned that “perceived inconsistency or unfairness in how and where restrictions are imposed could lead to social unrest and public disorder”. Sir Chris Ham, the former chief executive of the health thinktank the King’s Fund, said: “The evidence used by ministers when taking lockdown decisions should always be made public, especially as these decisions have a major impact on the lives of people affected. “Transparency is essential if public trust in the government’s decisions is to be restored, as already happens with Sage minutes.” Wajid Khan, the mayor of Burnley borough council, one of the towns placed under lockdown, said manner of Hancock’s announcement led Muslims to feel “scapegoated and blamed” and “used, confused and abused”. He said the government’s failure to publish the evidence behind Hancock’s claim would “exacerbate” distrust “towards the way decision-making affects those communities”. “It is in all of our interest to find out what led to this controversial decision,” he said. The DHSC has been contacted for comment.