Ex-chancellor Sajid Javid was reported to be incandescent with rage at a briefing to the Sunday Times newspaper that he was incompetent and should not replace Kwasi Kwarteng at the Treasury.
Mr Stein is considered an ally of Jeremy Hunt, who ultimately got the job – having previously worked for Mr Hunt’s 2019 leadership campaign.
Mr Javid was lined up to challenge Ms Truss at Prime Minister’s Questions on Wednesday, but ultimately did not ask his planned question. The aide was reported to be suspended just minutes before PMQs began.
ITV News reports that Mr Javid had demanded the suspension in exchange for dropping his question to the prime minister – whose leadership is on the ropes.
Mr Stein was Ms Truss’s senior campaign advisor during her Tory leadership bid this year.
UK news in pictures
19 October 2022: Salmon leap up Stainforth Force on the River Ribble in the Yorkshire Dales as they swim upriver to their spawning grounds during the annual Salmon migration (PA)
18 October 2022: Just Stop Oil protesters continue their protest for a second day on the Queen Elizabeth II Bridge, which links Kent and Essex and which remains closed for traffic, after it was scaled by two climbers from the group (PA)
17 October 2022: Hundreds of students take part in the traditional Raisin Monday foam fight on St Salvator's Lower College Lawn at the University of St Andrews in Fife (PA)
16 October 2022: A protester holds a placard during a march into central London at a demonstration by the climate change protest group Extinction Rebellion (AFP/Getty)
15 October 2022: A member of the public drags an activist who is blocking the road during a
14 October 2022: Germany’s Women’s double skulls during day one of the World Rowing Beach Sprint Finals at Saundersfoot beach, Pembrokeshire (PA)
13 October 2022: Family and mourners arrive at St Michael's Church, in Creeslough, for the funeral mass of 49-year-old mother of four Martina Martin, who died following an explosion at the Applegreen service station in the village of Creeslough in Co Donegal on Friday (PA)
12 October 2022: Motorists in Coventry pass trees showing autumnal colour (PA)
11 October 2022: A woman and her dog in the the North Sea at Tynemouth Longsands beach before sunrise (PA)
10 October 2022: Police officers remove a campaigner from a Just Stop Oil protest on The Mall, near Buckingham Palace, London (PA)
9 October 2022: A drummer plays during the Diwali on the Square celebration, in Trafalgar Square, London (PA)
He also previously advised Prince Andrew on media matters.
Downing Street declined to comment on the reports, which first appeared on the BBC and Sky News.
But a No 10 source said: "The prime minister has made very clear to her team that some of the sort of briefings that we have seen about parliamentary colleagues are completely unacceptable and they must stop."
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