Steve Bannon and other former top officials in the Trump administration are facing legal peril for defying subpoenas issued by the House select committee investigating the Capitol attack, as the panel prepares to pursue criminal referrals for non-compliance.

The legal jeopardy for Bannon – who is expected to be held in contempt by the committee on Tuesday – is anticipated after it emerged in a letter to his attorney, obtained by the Guardian on Monday, that he had claimed executive privilege protections on materials unrelated to the executive branch.

The House select committee chairman, Bennie Thompson, also said in the letter that even if the panel entertained the claims of executive privilege, Bannon had no basis to ignore the order since not even a president could grant him immunity from a House subpoena.

The dual legal arguments in the letter, which served as Bannon’s final warning to cooperate a day before the select committee is expected to hold him in contempt of Congress, underscores the weakness of the executive privilege claim advanced by Donald Trump.

The Guardian first reported that the former president would instruct his top four aides subpoenaed by the select committee – White House chief of staff Mark Meadows, his deputy Dan Scavino, defense department aide Kash Patel, as well as Bannon, his former chief strategist – to defy the orders.

But even though Bannon is alone in defying a subpoena after Meadows and Patel were “engaging” with the panel over the potential scope of their cooperation and Scavino was served late, the letter shows similar attempts to invoke executive privilege appear treacherous.

The missive from the select committee came in response to a previous letter from Bannon’s attorney, Robert Costello, who insisted his client was precluded from complying with the subpoena until claims about executive privilege by Trump were settled in a court ruling.

Thompson said in his response that he rejected the entire argument leaning on Trump and considered Bannon as having violated federal law after he “wilfully failed to both produce a single document and to appear for his scheduled deposition”.

The chairman of the select committee said the executive privilege claim could not apply in Bannon’s case, because the panel had in part sought his contacts with members of Congress and the Trump campaign, which are not covered by the presidential protection.

Thompson added that even if the select committee accepted that some materials demanded by the panel were shielded by executive privilege, Bannon would not be exempt from complying with a congressional subpoena.

The chairman also said that the select committee believed Costello’s interpretation of a previous case involving the testimony of a Trump administration official – the former White House counsel Don McGahn – actually undermined Bannon’s argument to defy his subpoena.

In the case with McGahn, said Thompson, the US district court for the District of Columbia ruled that even senior White House aides were not entitled to absolute immunity from testifying. McGahn, pursuant to that ruling, ultimately testified to Congress in July.

Furthermore, the citation referring to McGahn used by Costello “makes clear that a president lacks legal authority to order an aide not to appear before Congress based on a claim of executive privilege,” Thompson said.

The legal rebuttals outlined in the letter were specific to Bannon’s non-compliance. But a source close to the select committee said the same arguments would be pressed against Meadows, Scavino and Patel should they also attempt an executive privilege claim.

And with a reversal in position from Bannon not forthcoming before a 6pm ET deadline on Monday, the select committee is now expected to proceed with a vote recommending the House refer him to the US Attorney for the District of Columbia for criminal prosecution.

The letter outlining the select committee’s arguments was earlier reported by the Washington Post.

The developing contours of the select committee’s move to secure Bannon’s conviction – which would carry a maximum penalty of a one year sentence in federal prison and up to $100,000 in fines – came as Trump filed a lawsuit blocking the release of his White House records.

Trump filed a lawsuit with the DC district court to stop the National Archives from releasing records to the select committee a tranche of records, after Joe Biden’s White House counsel, Dana Remus, declined to assert executive privilege protections.

The Guardian first reported that Trump would sue to block the release of records from his administration last month. Trump’s legal counsel has indicated the former president is seeking to shield about 50 documents from scrutiny.