Not a white flag but a cream blazer was what Victoria Starmer chose to wear to accompany her husband, the prime minister, to vote on Thursday morning. She follows in a long line of women who have mobilised the power blazer at high-stakes moments.

Starmer’s, which looks much like a £1,690 ivory Alexander McQueen crepe design, comes hot on the lapels of another. In episode one of the new series of Amandaland, Amanda wears a beige double-breasted iteration in a high-stakes fictional moment: to give a toe-curling talk about her (not shallow) lifestyle brand Senuous as part of careers week at her kid’s school. Earlier in the week, the Princess of Wales launched the Foundations for Life report wearing a creamy beige high-waisted Roland Mouret suit.

The cream blazer has, according to the stylist and DC-based fashion consultant Lauren Rothman, who styles politicians and business people, “a professional, creative aesthetic to it that says: ‘I’m in my own lane of power dressing, and that requires standing out while still signalling competence.’”

Rothman refers to the blazer in general as “the third piece”: “the layer that turns clothing into presence”. Blazers, she says, “create visual structure, and structure is psychologically associated with authority, preparedness, competence”. Physically, she says, blazers change “how they carry themselves by the sharpening of framing the body in a powerful way”.

A blazer in a cream, or close-to-cream, colour has an added layer. “It’s a high-visibility neutral,” she says. “Psychologically that behaves very differently than black … It attracts attention. Where dark colours recede, white and cream advance. And so it really changes the power dynamic of how a woman occupies a room or a space.”

The oversized, off-white Marc Jacobs blazer Harry Styles wears in his new video for Dance No More is certainly a case in point, particularly in tandem with his bright red short-shorts.

In the case of Starmer, next to the dark tailoring of her husband, it denotes “the modern evolution of power dressing”. The same could be said for Melania Trump, appearing next to her husband to welcome the British king and queen to the White House last week wearing an off-white Ralph Lauren blazer and matching skirt. Perhaps there’s something in the contrast that Hillary Clinton was hoping to weaponise in 2016 when she wore a Ralph Lauren cream wool crepe blazer to take on Donald Trump in the third presidential debate during which sexual assault allegations against him were raised.

As well as authority, Rothman says, creamy hues offer approachability. It’s perhaps this that made second lady of the US, Usha Vance, wear a cream blazer recently in a YouTube episode of Storytime With the Second Lady, where she and Curb Your Enthusiasm actor Cheryl Hines read The Story of the Three Little Pigs.

Also, there’s a status inherent in it. “Not anybody can wear white,” states Rothman. “It gets dirty.” Of course, anyone needing to get the tube, rather than get in a car driven for them, may be more hesitant.

Then there are historical implications owing to its close proximity to suffragette white – in photos, some of these power blazers appear more white than cream. “Using white during major symbolic moments in the political leadership world can become shorthand for female authority, solidarity, institutional breakthrough,” says Rothman.

Small wonder Alexandria Ocasio-Cortez has in the past mobilised the power of a caped white blazer, wearing what is believed to be a Zara design to the 2019 State of the Union address.

Rothman often advises her clients to wear a white blazer. The only time she wouldn’t? “If it doesn’t make sense seasonally … and I do have some chronic spillers.”