The UK government’s controversial Freedom of Information (FOI) screening unit told the housing department to alter responses to requests for information about the Grenfell Tower fire, openDemocracy can reveal.

The Clearing House, a Cabinet Office unit that vets FOI requests from journalists and others, is the subject of two ongoing inquiries. Concerns were previously raised about the extent to which the unit allows the government to coordinate FOI responses.

Now, openDemocracy has found that the secretive unit interfered in responses to FOI requests sent to the Department for Housing, Communities and Local Government in the wake of the Grenfell tragedy, which claimed 72 lives in 2017.

The Grenfell fire led to a surge in FOI requests, with a desire for greater transparency from the government about what had happened – as well as greater transparency around building regulations and fire safety.

But just days after the tragedy, the Clearing House wrote to the housing department, saying: “It would be helpful if we could see a list of responses you have received so far along with how you intend to reply to each individual request.”

The Clearing House also “suggested advice” on what information should be made public. But the government has now refused to release this advice, claiming that doing so “would unacceptably erode the thinking space” of officials.

Emails released to openDemocracy have been heavily redacted, with the advice removed.

In at least one instance, the Clearing House interfered to block information from being released. In an email to the housing department, the Clearing House wrote: “We’re content with these draft responses apart from [REDACTED]”. After that follows three lines of blacked-out text.

openDemocracy has appealed against the government’s decision not to release the emails in full.

In emails, Clearing House staff also asked the housing department to sign off on responses to requests for information about Grenfell.

Details of the Clearing House’s role in directing responses to FOI requests about Grenfell come as openDemocracy revealed that the British government has spent at least £500,000 on legal costs fighting the disclosure of information under FOI. A poll commissioned by openDemocracy found that seven in ten British voters are concerned about the government’s attitude to transparency.

Responding to openDemocracy’s latest findings, Labour MP Andy Slaughter said: “We are constantly told by ministers that getting to the truth of what happened at Grenfell Tower and ensuring such a tragedy never happens again is their first priority.

“But the trail openDemocracy has followed shows that not only are the housing department reluctant to answer basic questions about fire safety, but they are deferring to the now-infamous Clearing House for permission to respond to Freedom of Information requests.”

He added: “It is no wonder so little progress has been made to expose and rectify the mistakes that led to the Grenfell fire, when the government cares more about its image and news management.”

Katherine Gundersen, deputy director of the Campaign for Freedom of Information, told openDemocracy that the government “appears to be withholding the Clearing House’s advice not to avoid prejudicing the Grenfell inquiry but to protect the Cabinet Office’s ability to develop government policy on answering requests about Grenfell. This seems absurd.”

Between June and August 2017, FOI requesters asked for information on issues such as fire safety, cladding, sprinkler systems and building regulations, as well as requesting copies of emails relating to Grenfell from government ministers and officials.

Emails indicate that the Cabinet Office was sent a spreadsheet of Grenfell-related requests on 22 June 2017, eight days after the tragedy. The housing department said it was “interested in your views on approach”.

The Cabinet Office appears not to have responded for weeks, saying: “With sincere apologies for the delay, please find attached some suggested advice regarding your FOI requests”.

‘Profound lack of transparency’

The Clearing House was at the centre of a landmark legal victory by openDemocracy earlier this year, amid allegations that it was blacklisting requests from journalists and campaigners. The judge criticised a “profound lack of transparency about the operation” that might “extend to ministers”. Documents submitted to court by the Cabinet Office were also said to be “misleading”.

openDemocracy has previously revealed how the Clearing House has blocked requests for information and has caused significant delays for requesters.

In one case, the unit blocked the release of sensitive files about the contaminated blood scandal, which claimed the lives of thousands across Britain, encouraging the Treasury to avoid releasing important historic documents.

Politico also recently revealed how the Clearing House worked to block the release of documents to journalists, against the advice of the Department for International Trade’s own information officers.

The Cabinet Office was criticised for a “lacuna in public information” about how the Clearing House coordinates FOI requests referred to it by government departments and agencies.

The legal victory has sparked a parliamentary inquiry into the operation of the Clearing House. Last week, openDemocracy revealed that the Cabinet Office is set to review the Clearing House to “identify if or where guidance might be improved or clarified”.

Earlier this year, openDemocracy revealed how the housing ministry told local authorities they can block FOI requests that may identify high-rise buildings with potentially lethal aluminium cladding.

A Cabinet Office spokesperson said openDemocracy’s claims about the Clearing House’s role in dealing with FOI requests about Grenfell was “false”, adding: “The Clearing House provides an advisory function and does not direct departments. It has not sought to block the release of information in these cases.

“A Clearing House function has existed since 2004 to ensure there is a consistent approach to dealing with FOIs across government and that requests for particularly sensitive information are handled appropriately.”