T is for totally optimistic: Depressed? Just pull on an Antoni & Alison T-shirt with a snappy, happy slogan and you'll soon feel better. Tamsin Blanchard takes the cure during London Fashion Week

'A T-shirt can be as fantastic as a Balenciaga ballgown. If you totally focus, you can make it the best thing ever,' say Antoni Burakowski and Alison Roberts, British designers who have proved that it is possible to take part in London Fashion Week and take on the world.

Last year, the pair found fame they had never sought - after they sued the fashion giant Giorgio Armani and won. Armani's design studio copied Antoni & Alison's 'I feel absolutely amazing fantastic incredible brilliant' T-shirts and doubtless thought it could get away with it. Perhaps Armani had forgotten about David and Goliath.

During London Fashion Week - now under way - Antoni & Alison join 29 other bright young things showing their wares at St Christopher's Place. The new collection is called 'Antonimodernalison' and once again is based on T-shirts superimposed with words.

But there's more to it than that. The collection, like all those by Antoni & Alison, is infused with an optimism people cannot get enough of. At The Clothes Show Live in Birmingham last December, their stand was a mob scene. Mothers, daughters, girlfriends, boyfriends were ecstatic about a T-shirt carrying the upbeat message: 'Love it]'

T-shirts, and knickers big and small, are pared down to the simplest of shapes, and printed with snappy, happy phrases and symbols. The real appeal of Antoni & Alison is that their minimal clothes are about upbeat thoughts and dreams.

In the past two years, business has boomed. The pair even receive fan mail. This month, their first licence deal - a watch made by Tikkers - is launched. And they are preparing to bring out a small knitwear and dress collection next October. 'It's so incredible the way it's been happening,' exclaims Antoni.

Antoni & Alison met at Central St Martin's College of Art & Design, in London. Then they worked away in obscurity, creating offbeat collections that all related in some way to their lives. 'We did a whole collection based on us arguing, with big speech bubbles saying 'Aaaaaargh]' and dresses with ties around the necks to throttle each other.' One of their new T-shirts reads 'Give me space', another 'I can fly'.

Other collections have been entitled Be Beautiful, Painterly, Elements, and Warm. 'It was so cold in our studio we did a Warm collection with really thick, hairy, boiled wool, and bar-heater prints,' they say.

Before they got into T-shirts, Antoni & Alison treated fashion design like fine art. 'We didn't really want to sell,' says Alison. 'I didn't see the need to duplicate.' Ironic that more than 5,000 copies of the Love it] T-shirt alone have been sold.

The turning-point for them was two years ago, when they began to concentrate on T-shirts and knickers. The time had come to make something affordable. Underwear and T-shirts were ideal as they were simple enough to be made to perfection. And Antoni & Alison are perfectionists - the reason they vacuum-pack their clothes is to get them to the shops as 'fresh' as possible.

Now the packaging has become a trademark, although they never intended it to be so. 'Everything should be fabulous. Quality that people can afford,' says Antoni.

So instead of just buying a bulk load of T-shirts and printing them up, A&A spent eight months researching. Eventually, they found a traditional, family-run factory with original underwear machines from the Twenties. Here they could have fabric woven to the exact widths they wanted, and seams could be precision-sewn in rayon.

What makes A&A's T-shirts special is their flattering, slender fit, their super-soft cotton, their finish and the message hidden inside, just for the wearer. Last year the message was 'wear me be naked' and the message in the new collection is 'if it's a vision let me enjoy it'. Even the washing instructions are more friendly than most, simply stressing, 'look after this garment'.

The best thing about Antoni & Alison is their infectious high spirits. When I leave the designers' studio in Dalston, East London, and walk into the clear, sunny day, I think anything is possible. Yes, I can fly.

(Photographs omitted)