Behind every great leader... The rise and fall of the superadviser, and the future of Morgan McSweeney

From Rasputin to Cummings, aides have stepped out of the shadows at their peril. Tom Baldwin asks whether Keir Starmer's has made the same mistake

- Tom Baldwin

They always generate friction with their colleagues, sometimes act as lightning conductors by taking the blame for the boss’s failings, and occasionally cause the kind of power surge that blows the fuse box or threatens to set the whole system on fire.

These unelected “superadvisers” have been a feature of almost all recent governments. They first get talked up by the press as being more important than cabinet ministers or more fascinating than the prime minister. Then the trouble starts.

The latest figure from whom sparks have been flying is, of course, Downing Street's chief of staff, Morgan McSweeney. According to legend, he almost singlehandedly transformed the Labour party in opposition, before guiding it to election victory. Yet his growing legions of critics say that in government he has allowed a vicious culture of machination to develop. Certainly, the seemingly endless drumbeat of anonymous media briefings against ministers and civil servants from inside No 10 has drowned out or even contradicted Keir Starmer’s once-stated ambition for a politics that “treads more lightly on people's lives”.

The complaints about him came to a head two weeks ago. Although he wasn’t the government source who accused Wes Streeting, the health secretary, of plotting a coup, no one denies McSweeney was involved in a spectacularly inept briefing operation across many media outlets. This succeeded only in turning whispered rumours about the prime minister's potential ousting into front-page news.