A senator who received a voice message meant for another Republican on January 6 described the caller, Rudy Giuliani, as “walking malpractice”.

The piquant characterisation of the former New York mayor, then Donald Trump’s attorney and a leading proponent of his election fraud lie, was made in a text message sent by Mike Lee of Utah.

The text was included in the final report of the House January 6 committee, which was released late on Thursday. Reporters immediately scoured its 845 pages for new details of Trump’s attempt to overturn his election defeat, leading to the attack on the Capitol.

Lee’s comment is contained in a footnote to page 631. It says: “6 January 2021, text message from Senator Mike Lee to [national security adviser] Robert O’Brien at 10.55pm EST reading, ‘You can’t make this up. I just got this voice message [from] Rudy Giuliani, who apparently thought he was calling Senator Tuberville.

“‘You’ve got to listen to that message. Rudy is walking malpractice.’”

Giuliani was trying to contact Tommy Tuberville, from Alabama, before Congress reconvened to certify Joe Biden’s election victory, the process the rioters tried to stop.

Biden’s win was certified, though not before 147 Republicans in the House and Senate objected to results in key states, shortly after rioters sought lawmakers to capture and perhaps kill, some chanting that they wanted to hang the vice-president, Mike Pence.

The attack is now linked to nine deaths, including law enforcement suicides.

Giuliani’s message was reported at the time. Referring to the Trump team’s efforts in key states, he said: “I’m calling you because I want to discuss with you how they’re trying to rush this hearing and how we need you, our Republican friends, to try to just slow it down so we can get these legislatures to get more information to you.

“And I know they’re reconvening at eight tonight, but … the only strategy we can follow is to object to numerous states and raise issues so that we get ourselves into tomorrow – ideally until the end of tomorrow.

“I know [Senate Republican leader Mitch] McConnell is doing everything he can to rush it, which is kind of a kick in the head because it’s one thing to oppose us, it’s another thing not to give us a fair opportunity to contest it.”

McConnell would later vote to acquit Trump, in an impeachment trial arising from the Capitol attack, when conviction would have barred the former president from holding federal office again.

In contrast, legal authorities now seem inclined to agree with Lee’s assessment of Giuliani’s unsuitability to practice as an attorney.

Earlier this month, a preliminary disciplinary hearing of the Washington DC bar saw counsel argue that Giuliani, 78, should lose his license because of his attempt to undermine the election.

Defending himself, Giuliani said: “I believe that I’ve been persecuted for three or four years, including false charges brought against me by the federal government.”

Though his activities in support of Trump’s election subversion are the subject of numerous investigations, Giuliani has not been charged with any crime.

His license to practise law in New York, the city he once led, was however suspended in June last year.

Numerous reports and books have described Giuliani’s increasingly bizarre behaviour in his role as Trump’s attorney.

His biographer, Andrew Kirtzman, concluded that while Trump remains a political player, running for the Republican nomination in 2024, “Giuliani … [is] finished in every conceivable way.”