The Green party MP Caroline Lucas has called for an inquiry into a government unit intended to combat disinformation after it emerged she had been flagged by it for criticisms of ministers and government policy over Covid. Lucas, who lodged a subject access request along with the campaign group Big Brother Watch for details held on her by the counter-disinformation unit (CDU), said her inclusion in a series of reports amounted to “staggering overreach” by ministers. A government spokesperson said the work of the CDU and the now-defunct rapid response unit (RRU) media monitoring service, which also cited Lucas, was more broad, and that inclusion did not mean someone was suspected of disinformation. Among examples of information about Lucas held by the CDU was her inclusion in an RRU report on “vaccine hesitancy” based on what was described as a “prominent tweet” by her in 2021 arguing that booster vaccines should be sent to countries with shortages. In April 2020, she was featured in a CDU “Covid mis/disinformation report” after being critical of the way the government had purchased medical equipment during the pandemic. She was included again after a 2020 tweet she sent alleging poor government preparedness for a pandemic. On another occasion in 2020, she was included in an RRU briefing about a tweet she sent about prime minister’s questions, where Dominic Raab stood in for Boris Johnson. Lucas called him “arrogant, complacent and patronising”. In 2021, Lucas’s name appeared in a CDU report about “mis/disinformation narratives” ahead of that year’s local elections after she was included in a report in the Independent accusing Boris Johnson of being a liar. Officials argue that many of the examples come from the RRU, which they said acted largely as a straightforward media-monitoring unit. It was closed last year. The subject access request sets out that some of the examples of Lucas being named were not connected to potential disinformation, or “specific” to it. But Lucas, who has said she will stand down as an MP at the next election, told the Guardian she was alarmed at the work of the CDU, which was set up in 2019 as part of the Department of Culture, and is now within the Department for Science, Innovation and Technology. “This is simply staggering overreach from a government which has had, at the very least, a socially distanced relationship with the truth on multiple occasions in recent years,” she said. “The right of citizens to share entirely valid and objective criticisms of government ministers without fear of the consequences is a cornerstone of our democracy, and must be protected. If these disinformation units focused their efforts on genuine disinformation, dangerous conspiracy theories and foreign hostility, rather than my tweets, our politics might be in a better place. The CDU is clearly not fit for purpose, and a full investigation must be opened immediately.” Silkie Carlo, the director of Big Brother Watch, said the information showed the government “has dangerously blurred the lines between genuine disinformation and legitimate political dissent”. She said: “It’s particularly alarming to see an elected MP’s criticisms of the government logged in reports on so-called ‘election misinformation’, which could then be subject to the most harsh restrictions, including around election periods.” A government spokesperson said: “The CDU tracks narratives using publicly available information – it has never monitored the activity of any individual and has a blanket ban on referring content from journalists and MPs to social media platforms. “Mentions in subject access requests are not evidence that the unit considered those references to be disinformation. We are happy to discuss the work of the CDU with any parliamentarian should they wish to find out more about the important work of the unit.”