Liberal Supreme Court Justice Stephen Breyer is to retire, giving President Joe Biden an opening he has pledged to fill by naming the first black woman to the US’s highest court, sources have said.

Mr Breyer, 83, has been a pragmatic force on a court that has grown increasingly conservative in recent years, trying to forge majorities with more moderate justices right and left of centre.

He has been a justice since 1994, when he was appointed by President Bill Clinton.

Along with the late Justice Ruth Bader Ginsburg, Mr Breyer opted not to step down the last time the Democrats controlled the White House and the Senate during Barack Obama’s presidency.

Ms Ginsburg died in September 2020 and then-president Donald Trump filled the vacancy with a conservative justice, Amy Coney Barrett.

Mr Breyer’s departure, expected over the summer, will not change the 6-3 conservative advantage on the court because his replacement will be nominated by Mr Biden and almost certainly confirmed by a Senate where Democrats have the slimmest majority.

It will make conservative Justice Clarence Thomas the oldest member of the court. Mr Thomas turns 74 in June.

Senate Majority Leader Chuck Schumer said Mr Biden’s nominee “will receive a prompt hearing in the Senate Judiciary Committee and will be considered and confirmed by the full United States Senate with all deliberate speed”.

Among the names being circulated as potential nominees are California Supreme Court Justice Leondra Kruger, US Circuit Judge Ketanji Brown Jackson, prominent civil rights lawyer Sherrilyn Ifill and US District Judge Michelle Childs, whom Mr Biden has nominated to be an appeals court judge.

Ms Childs is a favourite of Representative James Clyburn, who made a crucial endorsement of Mr Biden just before South Carolina’s presidential primary in 2020.

Mr Biden has been focused on filling federal judicial nominations with a more diverse group of judges, and the Supreme Court has not been top of his mind during his first year in office, according to White House aides and allies.

A decision on a nominee has not been made yet, they said, and is expected to take a few weeks. But Mr Biden has expanded his pool of applicants by naming more black women to the bench.

White House press secretary Jen Psaki said on Twitter: “It has always been the decision of any Supreme Court Justice if and when they decide to retire, and how they want to announce it, and that remains the case today. We have no additional details or information to share from @WhiteHouse.”