Privacy campaigners have expressed alarm after the government revealed it had hired an artificial intelligence firm to collect and analyse the tweets of UK citizens as part of a coronavirus-related contract. Faculty, which was hired by Dominic Cummings to work for the Vote Leave campaign and counts two current and former Conservative ministers among its shareholders, was paid £400,000 by the Ministry of Housing, Communities and Local Government for the work, according to a copy of the contract published online. In June the Guardian reported Faculty had been awarded the contract, but that key passages in the published version of the document describing the work that the company would carry out had been redacted. In response to questions about the contract in the House of Lords, the government published an unredacted version of the contract, which describes the company’s work as “topic analysis of social media to understand public perception and emerging issues of concern to HMG arising from the Covid-19 crisis”. A further paragraph describes how machine learning will be applied to social media data. Silkie Carlo, the director of the civil liberties campaign group Big Brother Watch, which discovered the updated contract, expressed alarm at the details. “This is effectively AI-powered mass political surveillance, and it’s been done in a very secretive way, apparently to inform policy,” she said. “It seems from the contract this social media monitoring has been going on for three months, and machine learning has been used for that time. We don’t know what the impact is.” A Faculty spokesperson declined to comment on the criticism, but said that the project analysed public posts from Twitter containing words relating to the pandemic, such as “covid” or “coronavirus”, as part of an endeavour to help the government detect emerging issues relating to the pandemic in local communities. They said personally identifiable information, such as Twitter usernames or profiles, was stripped out from the data at the point of collection, meaning it would be impossible to use the information to profile any individual or group of people. Carlo expressed scepticism that social media posts would provide the government with an accurate insight into public attitudes. “Twitter is not representative of public opinion as a whole,” she said. “I think there are a lot of questions to be asked about the premise.” An MHCLG spokesperson said: “We are satisfied that the service provided by Faculty was of a high standard, and delivered on value for money.” They added that the contract expired in July. The MHCLG social media work is one of several government contracts awarded to Faculty relating to coronavirus. In March an existing contract to support the NHS with AI initiatives was expanded so that the firm could help create a “coronavirus datastore” for the government, visualising NHS data to help inform ministerial decision-making. The company has several links to figures in the Vote Leave campaign and the Conservative party. Two of its investors, Theodore Agnew and John Nash, are current or former Conservative ministers. In 2016 the firm was recruited by Cummings to provide data science and machine learning technology for the Vote Leave campaign. The work was carried out by Ben Warner, the brother of Faculty’s CEO, Marc Warner. Ben subsequently worked on the Conservative party’s 2019 general election campaign, and was later recruited as a data science adviser to Downing Street. Last month the Guardian reported Cummings had paid more than £250,000 to Faculty via his private consultancy firm, Dynamic Maps. Both parties have declined to explain what the payments were for. Faculty has previously said it would no longer accept political work. The Scott Trust, the ultimate owner of the Guardian, is the sole investor in GMG Ventures, which is a minority shareholder in Faculty.