LONDON, Feb 21, 2009 (AFP) - Vivienne Westwood took her inspiration from naughty schoolgirls for her latest collection on Saturday as London Fashion Week swung into action with a mix of austerity and irreverance.

Westwood based her new pret-a-porter line on the British school-days novel "St Trinian's", turning the stripes of a traditional school uniform into sharp suits and dresses fixed with a scoop neck and a bow.

Sexy, fun and eminently wearable, the clothes included tartan skirts, jackets that looked as if they had just been shrugged off by a surly teenager, red satin balloon trousers mixed with a schoolyard red cardigan and a sweater in rich purple with big sleeves, ribbed body and scoop neck.

The mood was both defiant and energetic -- reflected as the models bounded on to the stage with Westwood at the end -- and topped off a day of catwalk shows that showed similar refusal to be cowed by the economic crisis.

There was a nod to sobriety with muted colours and an emphasis on sharp tailoring, but with the exotic feathers, refined prints and the abundance of fur, you could be forgiven for thinking the good times were back.

Graeme Black took his inspiration from visiting a rock and mineral collection at London's Natural History Museum -- the lawns of which host the main LFW tents -- mixing soft and smooth in texture and colour.

Rock strata were simulated in lines of different tones handpainted onto cashmere, as well as in the feathers that lined wide collars, giving a glimpse of luxury to otherwise classic coats in earthy colours.

One dark grey coat revealed a furry collar and crystals inside the sleeve, suggesting the sparkling inside of a rock cracked open, while fur coats were similarly pulled back to reveal jewelled sexy skin-tight dresses.

Fur was also present at John Rocha, who gave the appearance of austerity with his traditional black, as well as new sculptural shapes that cocooned the figure in shifts, or emphasised the hips with layering and detail.

But the crystal-encrusted necklines, bright geranium red and gold fabrics and sparkling head pieces offset this mood, while fitted jackets were lifted by the addition of tweed ruffles.

Across town, the trend-setting high street chain Top Shop, which will shortly open its first store in the United States, took a futuristic angle with hoodies and sweat pants in Day-glo or printed with scenes from space.

Introduced to the music to "Close Encounters of a Third Kind", the show was dominated by figure-hugging dresses layered over leggings and oversize parkas, heavy copper zips and metallic leather adding an industrial edge.

It was also a trip back in time, continuing the Eighties revival with geometric designs, stretched denim and sparkly socks.

Basso & Brooke also looked back, this time to 18th century France, for inspiration for its prints that were laid onto sharp, classically cut dresses.

In bold colours, the designs were laid out in patchwork across the material, accentuating the figures' waist or neckline, or replacing where a belt or collar might be.

Cut from light silks, they seemed more suited to a spring-summer than autumn-winter collection.

Jenny Packham also infused her collection with a light touch, using flowing fabrics for full-length or flapper-style gowns, but this was offset by heavy crystal jewelling along the neck, waistline and even used to form a skirt.

by Alice Ritchie