Jonathan Powell is considering quitting as the UK’s national security adviser after complaining of “exhaustion and stress”, The Telegraph understands.

The Downing Street aide, whose wife was recently accused of backing Palestine Action, the proscribed organisation, has been “talking about leaving for a long time”, according to his friends.

It comes amid mounting speculation over Mr Powell’s future after his wife was accused of backing Palestine Action.

Ms Helm, whose husband is Britain’s chief negotiator with Israel, wrote on X on Thursday: “God help us authors who support Palestine and Palestine Action.”The journalist and author was responding to a clip of someone criticising Sally Rooney, a fellow author, after her novels were withdrawn from sale in the UK because of her support for the organisation.

While Ms Helm’s tweet does not directly say that she supports Palestine Action, it has been interpreted as support for the group.

The Metropolitan Police had been assessing Ms Helm’s social media post, but confirmed on Saturday that they would not be taking any action against her as it did not meet the criminal threshold.

Sarah Helm’s tweet has been interpreted as support for Palestine Action, a proscribed terrorist group On Friday night she published another post on X, thanking her “supporters” and adding: “As an 83 yr old survivor of the Nakba and one of my many friends in Rafah (now obliterated) said to me when I was last there, ‘keep writing Sarah we need all the pencils we can get’.”Downing Street has distanced itself from Ms Helm’s posts. “These views are held by an individual who does not represent the government in any capacity,” a government spokesman said.

Reports that Mr Powell was planning to leave his Downing Street post by the end of the year first emerged in February. The aide has faced increased scrutiny following a series of controversies.

Mr Powell’s deal to hand sovereignty of the Chagos Islands over to Mauritius provoked a political row after it emerged that Britain would pay £35bn over 99 years to lease back Diego Garcia, which hosts a military base. The deal has now all but collapsed after Donald Trump withdrew his support.

Mr Powell also helped broker Sir Keir Starmer’s closer relationship with China, which culminated in the former prime minister’s visit in January.

Mr Powell has been involved in a series of controversies A No 10 source has denied that Mr Powell has any plans to step down from the role.

Ms Helm, the former Jerusalem correspondent for The Independent, has been highly critical of Israel since the outbreak of the war in Gaza. The day after the Oct 7 attacks, when Hamas terrorists killed an estimated 1,200 people in Israel and abducted 251 hostages, she wrote on X that Gaza was a “strange surreal prison” where Palestinians were “imprisoned without charge, herded there in 1948 after the UN decreed the new state Israel shd [sic] have their homes and land”.

A spokesman from Campaign Against Antisemitism said: “This is gobsmacking. Clearly, the police need to investigate and Sarah Helm must face the full force of the law, just like others who appear to express support for any proscribed terrorist organisation.

“But this raises extremely serious questions for Jonathan Powell and the Government. Spouses are entitled to independent views, but plainly Mr Powell, who leads on our country’s national security and has been intricately involved in our Middle-East diplomacy, must publicly denounce this rhetoric if he is to continue in post.

“If the wife of Britain’s top diplomat appears to openly support a proscribed terrorist organisation opposed to Israel’s existence, what message does that send to British Jews, many of whom are currently living in fear.”Palestine Action was proscribed by the Government under terror laws in 2025 after protesters allegedly broke into RAF Brize Norton and caused £7m of damage. More than 3,000 people have since been arrested for expressing support for the group. Supporting a proscribed organisation can lead to a maximum penalty of 14 years’ imprisonment.

Defend Our Juries, a campaign group opposed to the ban on Palestine Action, praised Ms Helm for appearing to defy the ruling.

A spokesman for the organisation said: “Thank you to Sarah Helm for defying this absurdly authoritarian ban on Palestine Action. The ban has led to more than 3,700 arrests of priests, pensioners and peaceful protesters for holding cardboard signs, and is now driving the books of one of the most acclaimed authors of our time off the shelves of British bookshops.

“How can Andy Burnham’s government possibly defend this ban in the Supreme Court next month when his own national security adviser’s wife has openly defied it? This unprecedented attack on free speech in our country is plainly unsustainable.”

Since its founding in 2020, Palestine Action has conducted a campaign of trespassing, vandalism and property damage against companies and buildings in the UK that it claims are linked to Zionism.

In August, Donald Trump, the US president, declared Palestine Action a global terrorist organisation, adding it to a list that includes Hamas, al-Qaeda and Islamic State.

Mr Powell has continued in his role as Britain’s national security adviser under Andy Burnham, travelling to Israel earlier this month to lead the British consulate discussions.

Relations between the UK and Israel reached their lowest ebb in decades in September after Ed Miliband, the Foreign Secretary, announced a ban on the import of goods from illegal Israeli settlements in the West Bank.

In response, Israel announced a series of retaliatory measures including the closure of the nearly 200-year-old British Consulate General in East Jerusalem. Representatives for Ms Helm have been approached for comment.