Donald Trump’s longtime ally Steve Bannon was taken into custody on Monday after surrendering at a federal prison to begin a four-month sentence on contempt charges for defying a subpoena in the congressional investigation into the US Capitol attack.

Bannon arrived at the Federal Correctional Institution in Danbury, Connecticut, around noon and was formally taken into federal custody, the Bureau of Prisons said.

Speaking to reporters, Bannon called himself a “political prisoner”, said former president Donald Trump was “very supportive” of him and slammed Democrats, including Attorney General Merrick Garland.

“I am proud of going to prison,” Bannon said, adding he was “standing up to the Garland corrupt DOJ”.

Steve Bannon speaks to supporters with placards outside Danbury Federal Correctional Institution alongside Marjorie Taylor Greene
Steve Bannon speaks outside Danbury Federal Correctional Institution as Marjorie Taylor Greene listens (Julia Nikhinson/AP)

Shortly before he arrived to surrender, a small group of supporters, including Representative Marjorie Taylor Greene, the Republican from Georgia, gathered on the side of the road outside the prison. People cheered as Ms Greene and Bannon spoke during a news conference, holding up flags and signs supporting Bannon as a small group of protesters shouted “Lock him up” and “Traitor”.

A Biden supporter taunted Bannon by yelling “traitor” while Trump supporters tried to shout her down. Police had to stop traffic to allow the black SUV that Bannon was in to pull out of a church parking lot where Bannon’s supporters had gathered.

A judge had allowed Bannon to stay free for nearly two years while he appealed but ordered him to report to prison Monday after an appeals court panel upheld his contempt of Congress convictions. The Supreme Court on Friday rejected his last-minute appeal to stave off his sentence.

A jury found Bannon guilty of two counts of contempt of Congress: one for refusing to sit for a deposition with the January 6 House Committee and a second for refusing to provide documents related to his involvement in the Republican ex-president’s efforts to overturn his 2020 election loss to Democrat Joe Biden.

Defence lawyers have argued the case raises issues that should be examined by the Supreme Court, including Bannon’s previous lawyer’s belief that the subpoena was invalid because Mr Trump had asserted executive privilege. Prosecutors, though, say Bannon had left the White House years before and Mr Trump had never invoked executive privilege in front of the committee.

Bannon’s appeal will continue to play out, and Republican House leaders have put their support behind stepping in to assert the January 6 committee was improperly created, effectively trying to deem the subpoena Bannon received as illegitimate.

Another Trump aide, trade adviser Peter Navarro, has also been convicted of contempt of Congress. He reported to prison in March to serve his four-month sentence after the Supreme Court refused his bid to delay the sentence.

Bannon is also facing criminal charges in New York state court alleging he duped donors who gave money to build a wall along the US-Mexico border. Bannon has pleaded not guilty to money laundering, conspiracy, fraud and other charges, and that trial has been postponed until at least the end of September.

Mr Trump had previously pardoned Bannon, his former chief strategist, in the final hours of his White House term as part of a flurry of clemency action.

Bannon had been charged federally with duping thousands of donors who believed their money would be used to fulfill Trump’s chief campaign promise to build the wall along the southern border. Instead, prosecutors alleged he diverted over a million dollars, paying a salary to one campaign official and personal expenses for himself. His co-defendants were not pardoned.