LONDON — The U.K. Foreign Office will review “serious information failures” that led to ministers being unaware of “abhorrent” social media posts by the British-Egyptian activist Alaa Abd El-Fattah, Foreign Secretary Yvette Cooper said Monday evening.

Prime Minister Keir Starmer on Friday said he was “delighted” Abd El-Fattah was back in the U.K. after he was released from prison in Egypt after successive British governments had campaigned for his release. The case has been a “top priority for my government since we came to office,” Starmer added.

But Downing Street was later forced to condemn Abd El-Fattah after social media posts emerged, in which he said he considered “killing any colonialists and specially Zionists heroic,” and called British people “dogs and monkeys.”

In a letter to a U.K. parliamentary committee, Cooper said she, Starmer and Deputy Prime Minister David Lammy “were all unaware” of historic tweets by Abd El-Fattah. “We consider them to be abhorrent,” she said. Abd El-Fattah on Monday “unequivocally” apologized for the tweets.

Cooper said current and former ministers were “never briefed on these tweets when they spoke publicly about the case,” and civil servants in charge of the case “were also unaware” of them.

In her letter to the foreign affairs committee Cooper said she was “deeply concerned” that the re-emergence of the historic posts — and the social media posts by senior politicians on Boxing Day welcoming Abd El-Fattah’s reunion with his family — had “added to the distress felt by Jewish communities in the UK.”

It was clear there had been an “unacceptable failure” and that long-standing due diligence procedures had been “completely inadequate for this situation,” she added.

A senior Foreign Office civil servant has been asked to review the “serious information failures in this case” and the broader systems in place in the department for carrying out due diligence on high-profile consular and human rights cases to make sure they are “functioning properly for the future,” Cooper said.

Successive U.K. ministers campaigned for the release of Abd El-Fattah, who was convicted of “spreading fake news” in Egypt in 2021 for sharing a Facebook post about torture in the country.

He was granted British citizenship in December 2021 through his London-born mother, when the opposition Conservatives were in power.

The Conservatives and Nigel Farage’s Reform UK are now calling for Abd El-Fattah to be stripped of U.K. citizenship and deported.