Sir Keir Starmer has faced criticism for welcoming the arrival of Egyptian pro-democracy activist Alaa Abdel Fattah to the UK.
The backlash follows the emergence of past social media posts in which the campaigner appeared to call for the killing of Zionists.
A dual British national, Abdel Fattah left Egypt this week after being freed from prison.
He had been convicted in 2021 on charges of "spreading fake news" for sharing a Facebook post about alleged torture in the country.
The prime minister said he was “delighted” the activist had landed in the UK to be reunited with his family.
However, Shadow Justice Secretary Robert Jenrick called Sir Keir’s remarks a “serious error of judgement.” He pointed to Abdel Fattah’s past messages that endorsed violence against Zionists and police, stating the prime minister's comment amounted to a “personal, public endorsement” of the activist. “Nobody should be imprisoned arbitrarily, nor for peaceful dissent.
But neither should the prime minister place the authority of his office behind someone whose own words cross into the language of racism and bloodshed,” Jenrick said in a letter.
Cabinet ministers, including Foreign Secretary Yvette Cooper and Justice Secretary David Lammy, also published messages of support following Abdel Fattah's return.
The Jewish Leadership Council, a charity representing Jewish organisations across the UK, also criticized what it described as an "effusive welcome" from the government.