USP One carefully conceived treatment - synaesthesia is hard to pronounce but it is colourful, fun and engages all the senses.

Devised by Lush’s head perfumer and MD Mark Constantine and behavioural therapist Lady Helen Kennedy, with specially commissioned traditional English music by Simon Emmerson of The Imagined Village, the treatment is, hmmm, supposed to relax you enough to prise open your subconscious and liberate the "scent shapes and sound colours" in your imagination.

AMBIENCE You could walk blindfolded from Sloane Square and still find the Lush shop from the sweet smell alone. The spa is downstairs below the brightly lit shop piled high with girly coloured soaps and bath bombs.

It's calmer downstairs - there's no reception or relaxation room as such but a modern kitchen space with vintage decor such as retro tea cups and bird prints on the wall. There are 11 types of loose leave tea in glass jars, 11 types of bath bars on the sideboard and, on a wooden dresser, 23 Otrivine-style coloured bottles with handwritten tags like "Go Do", "Muscle" and Curious and quiet".

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In the centre of the kitchen is a paint flecked wallpapering-style table where a relaxed consultation takes places.

There are two treatment rooms, each with a roomy shower, and a bathroom packed with make-up refills and old-fashioned pefume atomisers.

QUALITY OF EXPERIENCE With just the one treatment on offer, I thought there'd be no choice paralysis. How wrong I was. There are - corresponding with the teas and bath bars - 11 versions of the treatment named after the state of mind you wish to achieve. These are chalked up on a blackboard and range from "Ambition" and "Feel Younger" to "Esteem" and "Enlightened". I chose the latter, after exploring several others with my therapist Mo, a cool dreadlocked Scot not at all in the corporate cookie-cutter mould of many young spa staff.

I then had to chalk the word "enlightened" on my own mini blackboard and choose one of the 23 bottles - I opted for the "forgiveness" labelled bottle, partly because of its shape and attractive plum colour.

In the darkened treatment room the liquid was poured into dried ice points on the wall and infused the room Top-of-the-Pops style with a white mist. Coupled with stainless-steel vats bubbling away on the side and colour-changing lights there was the air of mad scientist's lab about the room.

The all-over body massage was gentle and assured and used a creamy cocoa butter and shea butter based oil. The movements chimed at times with the music, which was bouncing off the walls out of five mini surround-sound Bose speakers. This neatly masked the sounds of staff on wooden floorboards above, which was fine as long as that wasnt the sound you'd left home to escape.

The music is dramatic and folky and the birdsong crisp and beautiful. It rounds off with Scarborough Fair just about the time I was enjoying a jojoba oil facial using hot and cold stones instead of fingertips. Prone, I was transported places in my imagination and felt unusually alert for the rest of the evening.

FOOD AND DRINK A nice cup of Enlightened tea - black tea base with the Enlightened oils and flavours. There's a bowl of seasonal fruit on the table. Hotel Chocolat is across the road and the Cadogan Arms gastropub across the road garnered five stars in a recent Time Out review and is a fine example of informal dining.

IN-CROWD Local women, Lush-ites, accidental tourists and out-of-towners taking a pampering break from retail therapy.

WALLET WATCH The Synaesthesia treatment costs £125 for 90 minutes. Facials, a deep-tissue massage and foot treatments are being introduced from November.

NEED TO KNOW Lush Spa Rooms – Through the Looking Glass, 123 Kings Road, London, SW3 4PL (020 7376 8348; www.lush.co.uk).

There are other Lush spas in Leeds, Poole and Kingston.

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