A British court is set to make a final decision on Monday on whether Julian Assange, the WikiLeaks founder, will be granted the right to appeal an extradition order to the United States, where he faces charges under the Espionage Act.

Mr. Assange has been held in a London prison since 2019, accused by the United States of violations in connection with obtaining and publishing classified government documents on WikiLeaks in 2010.

His case has slowly wound through the courts since his extradition was ordered by a London court in April 2022. Priti Patel, Britain’s home secretary at the time, approved the extradition two months later.

In February, the High Court heard Mr. Assange’s final bid for an appeal, and in March, the judges asked the U.S. authorities to provide specific assurances about his treatment if extradited.

In a hearing on Monday, the court will rule on whether those assurances — that Mr. Assange would not face the death penalty or be persecuted for his nationality and that he could seek the same First Amendment protections as a U.S. citizen — are satisfactory, and whether Mr. Assange can appeal his extradition.

While the timing for the judgment is still unclear, it could come as early as Monday afternoon, after the hearing ends. Here are the possible outcomes:

In a news briefing held last week, members of Mr. Assange’s legal team and his wife said that he could be put on a plane bound for the United States within 24 hours if the court ruled that he cannot appeal, potentially ending his yearslong battle.