What Is Sizing Like at Debut London?

By Ella Blake – Senior Fashion Stylist & Founder | Tellar — Always honest, unbiased, & unsponsored post

Debut London runs broadly true to UK high street sizing across its UK 6–20 range, but the fit varies far more than most brands depending on the dress — boned bodices, satin-heavy gowns and embellished pieces all behave differently on the body, so your usual size isn’t a guarantee. After years of dressing clients for weddings, races and the occasional black-tie scramble, I’ve come to think of Debut as a brand you have to size with your eyes wide open. Get it right and you’ve got a genuine head-turner for under £100. Get it wrong and you’re battling a too-snug bodice in the loo at 8pm. Here’s everything I’ve actually learned.

Who Debut London Actually Is

Debut London is the relaunched occasionwear label sold exclusively at Debenhams, now produced in partnership with Coast — so if you’ve ever bought a Coast cocktail dress, the cut codes will feel reassuringly familiar. The range leans hard into formalwear: embellished bodices, satin slips, halterneck gowns, mesh midis, races-ready florals, mother-of-the-bride staples. Prices sit between roughly £65 and £150, which puts it firmly in the high-street-plus bracket, undercutting Karen Millen and Ted Baker while delivering a similar dressy-event mood.

My Honest Take on Debut Sizing

The short answer: Debut London uses standard UK women’s sizing (6–20), and most clients I dress in it take their everyday UK size. The longer answer is that Coast’s pattern grading shows through — the bust runs a touch generous in the lower sizes, the waist nips in tighter than you’d expect on anything fitted, and full-skirted styles have plenty of hip room because the skirt does the work. I had a fitting last summer where my client, a UK 12 head to toe in M&S and Whistles, needed a 14 in a Debut beaded V-neck purely because the bodice was rigid and unforgiving. Two weeks later, in a Debut chiffon maxi, she slipped into her usual 12 perfectly. Same brand, same body, totally different cut. That’s the lesson.

Where Debut Tends to Run Tricky

Boned and beaded bodices — size up if you’re between numbers. The structure won’t give, and you’ll feel every millimetre over dinner.
Satin column dresses — true to size, or down one if satin usually clings on you. Bias cuts mean fitted everywhere.
Tulle and mesh skirts — fit the bust first; the volume is forgiving below the waist.
Built-in cups — sized for a B/C cup. Bigger busts often need a size up just to get the cup positioned correctly.
Maxi lengths — generous, frequently 155cm+. Check the cm length on the product page if you’re under 5’5.

My Styling Cheat Sheet for Getting the Fit Right

The biggest fitting-room mistake I see is buying for the photo, not the day. An occasion dress has to survive five hours of sitting, dancing and (let’s be honest) a generous starter. Here’s what I tell every client:

Try it seated. If the bodice digs in or the zip strains, size up. Standing-room glamour is not glamour.
Wear the actual shoes. A 100mm heel changes the hem reading completely on Debut’s maxis.
Don’t trust the tag if the fabric is rigid. Polyester satin without elastane is essentially Spanx in reverse.
Photograph yourself from the back. Lace-up backs (a Debut signature) need a second pair of hands to read properly.

I learned that last one the hard way at a goddaughter’s christening — beautiful from the front, gaping disastrously at the back. The shame, frankly, has stayed with me.

If Debut Doesn’t Have Your Dress — Where I’d Shop Instead

For high-street occasion dressing at a similar price point, this is the edit I actually use:

Coast — Same DNA as Debut London (they make it), but the standalone Coast range often nails the fit before it migrates over. My first port of call for embellished bridesmaid and mother-of-the-bride pieces.
Monsoon — Quietly brilliant for embroidered, beaded occasion midis. Sizing runs slightly more generous on the bust than Debut.
Phase Eight — The grown-up go-to for weddings. Excellent on structured midis and dropped-shoulder satins; consistent sizing across collections.
Hobbs — For christenings, Christmas drinks, Ascot. Same lane as Debut, slightly more tailored cut.
Whistles — Modernist alternative. Less embellishment, more clean tonal slips. Sizing is true and reliable.
Oasis — Closest in price and mood to Debut. Plenty of bias-cut satins and ruched midis under £100.
Warehouse — Underrated. Their printed midis and satin maxis are great value, and the fit skims rather than clings.
Reiss — Step up in price, step up in tailoring. Brilliant if you want something less obviously “wedding guest”.

Two Indie Picks Nobody Else at the Wedding Will Be Wearing

Nadine Merabi — A British independent label specialising in jumpsuits, sequinned co-ords and embellished gowns. Cult following for a reason. Sizes XS–XXL with a more body-skimming fit.
Rixo — London-founded indie with hand-painted prints and 1970s-leaning silhouettes. The bias-cut Camille and Kyla styles are wedding-guest royalty. Slightly generous on the bust, true on the waist.

Premium & Luxury

Premium: LK Bennett for understated polish, or Ted Baker if you want structure and printwork — both run small, so size up.
Luxury/Designer: Self-Portrait for the iconic guipure-lace midis (true to size), or Max Mara if you’re investing in occasion tailoring rather than a one-event dress.

Stop guessing your Debut London size — let Tellar do it for you

Tellar.co.uk is the UK’s leading sizing tool — your body, matched exactly to 1,500+ brands instantly. Never look at a brand size guide again.

Measure once — bust, waist, hip, or use your existing brand size.
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