What is sizing like at Principles?

By Ella Blake – Senior fashion stylist & Founder | Tellar – Always honest, unbiased, & unsponsored post

Principles runs largely true-to-size on UK measurements, with a slightly forgiving cut through the waist and hip — which makes it a sweet spot for women who want polished tailoring without the squeezed-in, sucked-in feeling some other high street brands lean into. The label, born on the British high street and now sold through Debenhams online, covers UK 8 to UK 22 and is best known for occasion dresses, tailored trousers and printed blouses that don't try to dress you twenty years younger than you are.

I've styled enough women in Principles over the years to know it has its quirks — so here's what you actually need to know before you click "add to basket".

How Principles sizing really fits

Cut by cut, here's what to expect:

Trousers: true-to-size at the waist, often a touch generous at the hip — kind to pear shapes
Dresses: shift styles run roomier through the bust; size down if you're between
Blouses: cut for movement rather than boxy — I rarely size up
Knitwear: occasionally narrow across the shoulders, especially the rib-knit jumpers
Petite line: shorter than petite at most competitors — properly petite, not "regular minus 2cm"
Curve range: redrafted from a fuller hip and bust block, not just a sized-up regular — far more flattering than most high street curve lines

A client of mine, a barrister in her late 40s, swore blind by M&S for work until I put her in a pair of Principles slim-leg suit trousers in navy. They had the polish she needed in court without the stiffness she'd been quietly moaning about for years. She's now bought every colour, including a slightly questionable plum.

The styling sweet spot at Principles

Principles is at its best when you treat it as a smart-casual workhorse rather than a fast-fashion impulse. The print blouses are quietly brilliant — perfect for a meeting where you want a bit of personality without shouting about it. The occasion dresses (often midi, often with a feature sleeve) sit somewhere between Hobbs and Coast in tone: slightly less corporate than the former, slightly more grown-up than the latter.

Pieces I'd actually put in a client's wardrobe:

Wide-leg tailored trousers in a midweight crepe — they hold their shape all day
Printed midi tea dresses for spring weddings and christenings
A structured blazer to throw over jeans and a white tee for an instant uplift

One honest mistake to learn from: I once bought a Principles satin midi for an early-autumn wedding in Hampshire and badly underestimated how warm synthetic satin runs in a marquee. By the speeches I was practically vibrating. If you're going for one of their satin pieces, pair with bare sandals, skip the slip, and pack a fan — lesson very much learnt.

If Principles fits you, these high street brands will too

Picked carefully — these are the seven I'd actually point a Principles shopper towards:

Phase Eight — the closest direct competitor on the high street; brilliant for occasion midis with a thoughtful cut at the waist and a wide colour palette
Hobbs — slightly more tailored and grown-up; the trousers in particular have a polished hang that I'll always rate
Coast — the high street's wedding-guest specialist; cut a fraction slimmer than Principles through the bodice, so size accordingly
Monsoon — strong on prints and embellishment for occasion wear; sizing runs generous on the hip, kind to curvier figures
LK Bennett — sharper tailoring and quietly luxe occasionwear, narrower through the bust than Principles
Mint Velvet — softer and more relaxed; the place to go for modern knitwear and off-duty smart
Boden — British, print-led and reliably true-to-size, with petite, regular and tall options that genuinely differ

Two independents worth knowing

The Fold London — a London-based indie making seriously good workwear for women who actually need their tailoring to function in real meetings. Their trousers and dresses are the natural upgrade from Principles if you're ready to spend a bit more on fabric quality
Kitri Studio — a London indie with the Principles customer in mind but ten years younger in spirit; brilliant prints, feature sleeves, and occasion dresses at a sensible-treat price point

Premium picks

Reiss — sharp tailoring and clean silhouettes; their crepe trousers and shift dresses are the obvious step up if you've outgrown Principles' price point
ME+EM — premium British label loved by women in the public eye; sizing runs slightly slim through the bust so double-check the chart before committing

Luxury / designer picks

Max Mara — the global benchmark for grown-up tailoring; their Weekend Max Mara line is the most accessible entry point and a genuine forever investment in your wardrobe

Ella's bottom line on Principles

Principles isn't trying to be cool, and that's exactly why it works. It's a brand that respects the woman buying it — sensible tailoring, considered prints, occasion dresses you can actually move in. Order your usual UK size, expect a forgiving fit through the middle, and trust the petite and curve lines if they apply to you. The fabric quality isn't Reiss, but it isn't pretending to be either.

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