Northern California immigration attorneys are reeling after learning of a controversial Trump administration decision to move hundreds of immigrant detainees’ court hearings out of San Francisco and to a new courthouse in Van Nuys, a neighborhood in north Los Angeles.

Legal aid attorneys and public defenders who represent the majority of detained immigrants in northern California say the government did not consult with them about the move.

They are concerned the transfer will in effect deny legal counsel to thousands of people facing deportation while undoing years of work by Bay Area not-for-profit organizations and local governments to provide more robust legal services for immigrants in US Immigration and Customs Enforcement (Ice) detention.

“It’s a clear step away from justice,” Raha Jorjani, director of the immigration representation unit of the Alameda county public defender’s office, said.

Under the new plan, starting 3 February, detainees held at the Mesa Verde Ice processing facility in Bakersfield will have their cases heard before judges in the Van Nuys immigration court, which opened last November.

Since Mesa Verde first opened in 2015, its detainees’ cases have been heard before judges in San Francisco’s immigration court. In recent years, most detainees have started appearing via video conference, rather than being transported to the court.

Responding to the growing numbers of detainee cases on the San Francisco immigration court’s docket, dozens of not-for-profit groups and government agencies teamed up to build a network of free legal resources, said Valerie Zukin, who coordinates the Northern California Collaborative for Immigrant Justice.

One effort Zukin oversees is the “attorney of the day” program, which ensures that an immigration attorney is in the courtroom whenever detainees at Mesa Verde and other Ice jails have their first hearings in San Francisco.

Zukin said that in 2017, only about 2% of these hearings in San Francisco’s court were being attended by an attorney to assist detainees. Today, her network of 35 legal aid groups covers more than 80% of hearings.

“We’ve been spending years training people and fundraising to make these programs possible,” said Zukin. “I can say with confidence there is no program like this in southern California yet.”

Studies have shown that detainees who have access to legal counsel are much more likely to obtain a bond for release and avoid being deported.

The Executive Office of Immigration Review did not immediately respond to questions from the Guardian about why the agency is transferring cases out of San Francisco. A spokesperson for Ice wrote in an email that it did not comment on “pending procedural changes”.

However, several immigration attorneys in the Bay Area confirmed the EOIR’s decision by sharing emails the federal agency had sent in the past few days to legal aid groups.

“We were hearing conflicting information from different sources over the past few months,” said Jorjani. In December, immigration attorneys asked EOIR officials if they were in fact considering the move.

“We were told not to worry,” said Jorjani.

But the rumors persisted. On 14 January, the Alameda county and San Francisco county public defenders sent a joint letter to the EOIR asking again about the possible move.

“We just received notice the court was moving all Mesa Verde cases to Van Nuys,” said Francisco Ugarte, the managing attorney for the San Francisco public defender’s immigration unit. “It would be one thing if they communicated to us this was their plan,” Ugarte said. “These are secretive decisions made by a secretive administration.”

Ugarte oversees a team of nine attorneys who defend indigent clients facing immigration cases that are often triggered after a person is arrested and charged with a crime. He estimated that over the past couple years, possibly 100 of the San Francisco public defender’s clients had been held in detention at Mesa Verde.

Jorjani said the abrupt decision would probably disrupt existing attorney-client relationships and would cut off detainees from access to the Bay Area’s robust legal community.

Some assistance is provided with public funding. In July 2018, the city of Oakland and Alameda county allocated a little over $1m to hire immigration attorneys to represent detainees. San Francisco allocated over $800,000 the same year to expand its public defender’s immigration unit.

Starting in 2016, Jorjani led a movement among Bay Area immigration attorneys to more aggressively challenge decisions made by immigration judges by filing petitions in federal district court. In recent cases, Jorjani’s team has succeeded in winning new bond hearings and the release of detained clients.

She said the transfer of cases to southern California would make it much more difficult for her team to provide this type of advanced defense.

“They need to halt this decision right now and get input from community stakeholders,” said Ugarte.