The justice secretary is to set out plans later to address prison overcrowding in England and Wales after concerns that jails may run out of space within weeks.
Shabana Mahmood has said emergency measures are needed to “pull the justice system back from the brink of total collapse”.
The plans are expected to include releasing some prisoners early, the BBC confirmed on Thursday.
Prisoners on “standard determinate sentences” will be released after they have served 40% rather than 50% of their sentence, government sources have confirmed.
There will be exemptions for sexual and serious violent offenders.
Prime Minister Sir Keir Starmer said the situation with prisons was “shocking” and showed “gross irresponsibility” from the previous government.
His Labour administration needed to “pick this up and we have to fix it”, he said, speaking during a news conference at the Nato summit in Washington.
Asked a question about the prisons announcement at the summit, Sir Keir added: “We’ve got far too many prisoners for the prison places that we’ve got and we soon will have.
“You should have enough places for your prisoners that judges are sending to prison.
